I've created this Web Page with a
two-fold purpose--first, of course, to document my own personal,
on-going actitivies and studies in the Middle Eocene Ione Formation
(roughly 49 to 45 million years old) of the Ione Basin, Amador
County, California. Then too, I hope that what I have to publish
here will perhaps in some small measure help generate, among
folks in cyberspace, a wider interest in the paleobotany, botany,
geology and general natural history of that specific section
of Amador County, Because it is my own humble, subjective opinion
that this is a topic brim-full of fascinating, stimulating things
to study. Ever since I discovered Eocene-age fossil leaves in
the Ione Basin on July 21, 1991, I've been hooked big-time, as
it were, and my personal quest to learn all that I can has inspired
many hikes through ancient geologic rock exposures that have
yielded, in several rather unexpected places, bountiful, beautiful
Eocene fossil leaves amidst the pastoral peace of the western
foothills of California's Sierra Nevada.
Perhaps a little background information
is now in order. After having discovered numerous prolific fossil
leaf localities in the Middle Eocene Ione Formation during occasional
visits in the early to mid 1990s--paleobotanical localities that
were new to science--I soon found myself traveling to the Ione
Basin on a more regular, scientifically motivated basis. These
were usually weekend trips to the Sierran foothills of Amador
County to try to collect from--and of course document--as many
of my newly found fossil leaf localities as possible. To the
best of my knowledge, nobody had ever really tried to do this
in a systematic manner.True, one or two geologists had already
noted the presence of "a few scattered" leaf fossils
in the Ione Formation of the Ione Basin, but no one had ever
seriously tried to collect specimens there, and then study them--and,
additionally, try to plot their occurrences on a topographic
map. From the very beginning, the Eocene Ione Formation Project
was a veritable "labor of love." Images from a number
of those early excursions to the Ione fossil fields can be found
in the section entitled, Days Of
Discovery.
My own participation in the project
came to an even sharper scientific focus when in late 1998 I
donated my many extensive collections of fossil plants from the
Ione Formation, Ione Basin, to the archival paleobotany collections
at the University California Museum Of Paleontology in Berkeley.
As far as I am aware, those were the very first fossil plants
from the Middle Eocene Ione Formation of the Ione Basin ever
placed in a museum. That donation led to a field trip to the
Ione Basin with paleobotanists Howard Schorn (retired Collections
Manager Of Fossil Plants at the University California Museum
Of Paleontology in Berkeley) and Dr. Diane Erwin (Collections
Manager Of Fossil Plants at UCMP)--a field trip documented at
this Web Page under the heading--Field
Trip 10-19-99. Another major highlight
came in July-August, 2002, when I was privileged to help Howard
Schorn conduct the first formal, scientific museum-sponsored
collection of fossil leaves from the Ione Formation of the Ione
Basin. See the Field Trip Summer 2002 section
of this Web site for all the details. More recently, Howard Schorn
and fellow paleobotanist, the late Dr. Jack A. Wolfe (passed
away in August, 2005--former member of the United States Geological
Survey), among others, hope to use suites of fossil leaves from
the Ione Formation of the Ione Basin to help determine the paleoelevations
and paleoclimate of the ancestral Eocene Sierra Nevada. This
is part of a broader project, funded by the National Science
Foundation, to analyze the numerous Eocene fossil floras of the
Sierra Nevada district, to run the fossil leaves through Dr.
Wolfe's famous CLAMP analysis--Climate Leaf Analysis Multivariate
Program. The system is an accurate methodology that uses the
relative size, shape and margins of fossil leaves to arrive at
the paleoelevations and paleoclimates of specific fossil floras.
The idea, eventually, is to determine, once and for all, just
how high the ancestral Eocene Sierra Nevada really was. Several
super-field trips have since followed. And they're all fully
documented, below.
Of course, this is all an on-going,
developing storyline. The Ione Basin fossil floras are pretty
much new to the paleobotanical community--hence, it is understandable
that they have not yet been described in comprehensive, monographic
detail. A few of the fossil forms are of course readily identifiable,
even under casual inspection--the fan palm fronds, for example,
plus the distinctive leaves from a species of climbing fern called
Lygodium kaulfussi, whose closest modern counterpart is
Lygodium palmatum--the sole species of climbing fern native
to North America; it's been spotted in Missississipi, Alabama
and Georgia north to New England. Interestingly enough, rather
common to abundant specimens of Lydodium kaulfussi have
been collected from a single locality in the Ione Formation of
the Ione Basin; it's a spot I discovered during one of my paleobotantical
investigations in 1992--a supremely prolific site known, appropriately
enough, as Lygodium Gulch. And, as a matter of fact, the Lygodium
remains recovered from the Ione Basin are the only known fossil
climbing ferns found west of the Rocky Mountains region to make
their way into a museum collection (at the University California
Museum Of Paleontology in Berkeley). This is mainly because localities
that yield fossil climbing ferns are quite rare, indeed--the
major producers of Lygodium in the United States remain the Middle
Eocene Green River Formation and the Upper Eocene Bridger Formation
of Colorado and Wyoming, respectively. Of course, with time,
paleobotanists will eventually identify and describe in great
scientific detail the fossil floras of the Ione Basin--so, as
the saying goes, "stay tuned" for more information--The
Project continues.
Geologic Background
The Ione Basin lies within Amador
County and northern Calaveras County in the western foothills
of California's Sierra Nevada. It's a scenic and economically
important geophysical province roughly 30 miles long by four
to seven miles wide whose primary surface exposures of Cenozoic
sedimentary rocks include the Middle Miocene Mehrten Formation,
the Lower Miocene Valley Springs Formation and what geologists
and stratigraphers alike call the Middle Eocene Ione Formation
(around 49 to 45 million years old); indeed, the Ione is a most-famous
geologic rock unit that yields world-renowned commercial deposits
of extraordinarily pure silica sand and high-grade kaolinite
clays--in addition to extensive accumulations of the rare and
valuable Montan Wax-rich lignite, which is mined commercially
at only two places in the world--the other Montan Wax site is
in Germany; lignite is classified as a type of low-grade coal
whose alteration of original vegetation has proceeded further
than in peat, but obviously not as great as anthracite coal.
Montan Wax occurs quite rarely in the geologic record when the
waxy substance which once protected the original plant leaves
from extremes of climate did not deteriorate, but instead enriched
the coal. Commercial applications for Montan Wax include polish,
carbon paper, road construction, building, rubber, lubricating
greases, fruit coating, water proofing and leather finishing.
All of these mineral commodities--silica sands, kaolinite clays
and Montan Wax-yielding liginites--have been mined in the Ione
Basin by open-pit methods for many decades. As a matter of fact,
today the Ione Basin lignites remain California's only actively
mined coal resources.
Geologically speaking, the Ione Formation
in the Ione Basin was deposited in floodplains, estuaries, lagoons,
deltas, mashes-swamps and marine waters (based on very, very
rare occurences of unquestioned marine mollusks) along the eastern
shores of a vast inland sea during Middle Eocene times--a sea
that had flooded, transgressed, what is now California's Great
Central Valley during the early portions of the Eocene, approximately
53 million years ago; but, in a curious display of geological,
marine cyclicity, sea waters had actually receded, regressed,
from the vicinity of the ancestral Ione Basin many millions of
years earlier, specifically during the early Tertiary Period,
roughly 60 million years ago. For approximately seven million
succeeding years, through most of the Paleocene Epoch of the
Cenozoic Era, the area now recognized as the western foothills
of the Sierra Nevada, Amador County, California, was left "high
and dry," exposed directly to an unrelenting hot, humid
tropical environment that left behind distinctive deposits of
laterite--which is an iron and aluminum-rich, deep-red soil zone
that forms today only in tropical environments capable of leaching
away soluble minerals (feldspar, biotite and chlorite, among
others), clays (kaolinite, illite and montmorillonite) and silica--places
such as India, for example, that experience cycles of hot-dry
winters combined with monsoon tropical rainfall, high humidity
and extreme temperatures.
When marine waters began to encroach
once again throughout the ancestral Central Valley during early
Eocene times, the prevailing climate had already become less
severely tropical than the environment that helped create the
laterite soil profiles--although most scientists agree that conditions
would still be classified as subtropical--that is, quite hot
and humid, with frequent, substantial amounts of precipitation.
Now, with sea waters rising again in the neighborhood of present-day
Ione Basin--transgressing, as geologists describe the process--the
numerous rivers and streams whose sources existed in the ancestral
Eocene Sierra Nevada to the immediate east began to "back
up;" gradients slackened; and the rivers proceeded to wander
in great braided, anastomozing courses along the floodplains.
Deposition of the Middle Eocene Ione Formation had begun..
Those rocks deposited earliest in
the local Ione geologic section (hence, they are the oldest)--strata
that have proved the most amenable to commercial mining--typically
consist of reddish-brown-colored kaolinite-rich clays and shales
and brilliant white quartz (silica)-dominated sandstones, plus
dull-brownish to black-hued Montan-Wax-bearing lignites that
accumulated in a semi-tropical climate of rather intense chemical
and physical weathering--a process that leached away all but
the more-resistant mineral constituents--quartz and kaolinite
clay. Probably the paleoclimate resembled modern-day southern
Florida in the southeastern United States; Occasionally, lignite
miners in the Ione Basin report finding huge fossil logs buried
with the more massive-beds of fossil peat. Higher in the Ione
section, in rocks of younger geologic age, the exposed clays,
sandstones and shales bear a greater percentage of feldspar,
biotite and chlorite. Such a dramatic change in mineral composition
signifies a major shift in paleoclimate during middle Eocene
times. Although conditions during deposition of the younger Ione
sediments were still dominated by extreme humidity, high rainfall
and warm semi-tropical temperatures, the once-rigorous climatic
regime of intense weathering had subsided considerably and a
general cooling trend began to prevail...
It was within these younger sedimentary
rocks of the Ione Formation that the paleobotanically invaluable
suites of fossil leaves were preserved. Approximately 49 to 45
million years ago, on occasion, the great system of braided rivers
that ran to the inland sea became engorged and overran their
banks, resulting in episodes of catastrophic, widespread flooding.
The high-energy rushing waters carried with them enormous quantities
of fine-grained sediments, plus abundant leaves torn from the
plants that inhabited the watercourses along the wide alluvial
floodplains. When flooding eventually subsided, many of the leaves
that had been swept along for the ride became winnowed, concentrated,
in overbank, backwater pools and within the many broad alluvial
mudflats, having been covered rapidly by feldspar and quartz-rich
sediments eroding from the ancestral Sierra Nevada. There, the
leaves remained protected between muddy, oxygen-depleted sedimentary
layers, vegetable tissues that were impervious to immediate decay
due to the high water table along the Eocene floodplain. Eventually,
geologic forces lithified--that is, hardened--the plant-bearing
ooze, preserving within, in stunning detail, the numerous fossil
leaves now stained a striking reddish brown (due to the presence
of iron minerals) on the brilliant white shales and reddish-brown
sandstones of the Ione Formation--abundant Eocene leaves only
awaiting eager fossil seekers to reveal them to their first light
of day in some 49 million years.
Indeed, here is one of the great
fossil leaf-bearing districts in all of California--an extensive
fossil field which is at last providing paleobotanists with their
first detailed look at the kinds of ancient plants that inhabited
an essentially sea-level floodplain paleoenvironment along the
western border of the ancestral Sierra Nevada mountains approximately
49 million years ago. It is an as-yet completely undescribed
fossil flora, relatively new to science--but one that will surely
provide lots of invaluable scientific information on the paleobotany
of the ancient Ione Basin.
The Low-Down
On Legal Issues
OK, here's the part of
this Web Site that I really dislike having to include, but it's
a necessary thing to do in this particular instance. Let's talk
about legal issues regarding fossil collecting activities in
the western foothills of the Sierra Nevada, California--the specific
regions discussed here where fossil plants occur in the Ione
Basin of Amador County...I know, I know, in an ideal world, most
paleontology enthusiasts would rather not have to worry about
such dreary and distracting concerns. We'd rather roam the countryside
for fossiliferous outcrops without having to fret about whether
we need permission to collect fossils at any given locality.
So, without any additional
"fanfare," let's explore the legalities of collecting
fossils in the areas discussed at this Web Site: First of all,
every fossil plant locality mentioned here is completely off
limits to unauthorized fossil collecting. In the western foothills
of the Sierra Nevada, each recently discovered paleobotanical
site in the Middle Eocene Ione Formation, Amador County, California,
occurs on private property; one needs explicit permission from
the land owners in order to collect fossil plants in the Ione
Formation. That same edict also holds true for all the other
fossil plant-yielding sites in the western foothills of the Sierra
Nevada--they're all off-limits if you don't have permission from
the land owners. There's no use belaboring the fact, I reckon.
That's just the way reality works in the western foothills of
the Sierra Nevada, California.
Images
Of Fossil Plants From The Ione Basin, Amador County, California
Click on the image for
a larger view. This is an essentially complete undescribed fossil
leaf from the Middle Eocene Ione Formation, western foothills
of the Sierra Nevada, California; reddish coloration is caused
by iron oxide residues in the rocks. The roughly 45 million-year-old
leaf came from a recently discovered locality on private property
in Amador County--a specific site currently under formal paleobotanical
study by Dr. Jack A. Wolfe (retired member of the United States
Geological Survey) and Howard E. Schorn (retired Collections
Manager of Fossil Plants at the University California Museum
of Paleontology in Berkeley), among others, who hope to use the
fossils to help approximate the paleoelevation of the ancestral
Sierra Nevada region during the geologic past. The fossil plants
from the Ione Basin constitute a completely undescribed flora--they
await formal identification by paleobotanists.
Please note: All fossil localities in the Ione
Formation of the Ione Basin presently occur on private property;
explicit permission from the land owners must be secured before
collecting fossils there.
Image #1--Fossil
leaf from the Middle Eocene Ione Formation, Ione Basin, Amador
County, California.
Image #2--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #3--Fossil leaf from a climbing fern, Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #4--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #5--Fossil leaves: leaf and climbing fern, Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #6--Fossil leaf from the,Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #7-- Fossil leaf from a climbing fern, Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #8--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #9--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #10--Fossil fan palm frond from the Middle Eocene Ione
Formation, Ione Basin, Amador County, California.
Image #11--Fossil leaf from a climbing fern, Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #12--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #13--Fossil leaves from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #14--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #15--Fossil leaves and a climbing fern from the Middle
Eocene Ione Formation, Ione Basin, Amador County, California.
Image #16--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #17--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #18--Fossil leaf from a climbing fern, Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #19--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #20--Fossil leaf and a climbing fern from the Middle
Eocene Ione Formation, Ione Basin, Amador County, California.
Image #21--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #22--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #23--Fossil leaf from a climbing fern, Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #24--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #25--Fossil leaf from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Images
Of Montan Wax-Bearing Lignite From The Ione Basin, California
Click on the image for
a larger image. This is a chunk of high-grade, Montan Wax-bearing
lignite from the Middle Eocene Ione Formation, Ione Basin, western
foothills of the Sierra Nevada, California. It came from the
walls of California's only active coal mine, where lignites bearing
the rare Montan Wax have been mined for several decades now.
Only two places in the world produce commercially minable deposits
of Montan Wax--the Ione Basin, California, and Amsdorf, Germany.
Lignite from the Middle Eocene Ione Formation of the Ione Basin
is a low-grade coal which has not been subjected to great forces
of heat and pressure through geologic time--hence, the waxy substance
of the original vegetal constituents has not been obliterated,
or altered.
Montan Wax occurs quite
rarely in the geologic record when the waxy substance which once
protected the original plant leaves from extremes of climate
did not deteriorate, but instead enriched the coal. Commercial
applications for Montan Wax include polish, carbon paper, road
construction, building, rubber, lubricating greases, fruit coating,
water proofing and leather finishing.
Image #1--A chunk of high-grade Montan Wax-bearing
lignite (low grade coal) from California's only active commercial
coal mine; also an image of California's only active commercial
coal mine----it's been processing lignites from the Middle Eocene
Ione Formation of the Ione Basin for several decades now.
Image #2--A chunk of high-grade Montan Wax-bearing
lignite (low grade coal) from California's only active commercial
coal mine, Ione Basin, California.
Image #3--A chunk of high-grade Montan Wax-bearing
lignite (low grade coal) from California's only active commercial
coal mine, Ione Basin, California.
Image #4--A chunk of high-grade Montan Wax-bearing
lignite (low grade coal) from California's only active commercial
coal mine, Ione Basin, California.
Images
Of Ophiomorpha Trace Fossils From The Ione Basin, California
Click on the image for
a larger view. This is an ichnofossil (trace fossil), called
scientifically Ophiomorpha, from the Middle Eocene Ione Formation,
western foothills of the Sierra Nevada. It is the fossilized
burrow of a species of shrimp-like animal, most likely a callianassid
shrimp. Here is a comprehensive description of just what Ophiomorpha
represents from the web page at http://www.envs.emory.edu/ichnology/Ophiomorpha.htm:
"Ophiomorpha is a
branching burrow with either horizontal, oblique, or vertical
box-like networks; the burrow exterior is characterized by a
knobby texture formed by a pelletal lining, but in some cases
only an internal mold of the burrow is evident. Ophiomorpha is
interpreted as a combined dwelling and feeding burrow made by
a shrimp-like animal; modern callianassid shrimp show the same
burrow geometry and pelletal reinforcement of their burrows."
Image #1--A
trace fossil called Ophiomorpha, a combined dwelling and feeding
burrow of a callianassid shrimp from the Middle Eocene Ione Formation,
Ione Basin, Amador County, California.
Image #2--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #3--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #4--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #5--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #6--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #7--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #8--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #9--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Image #10--A trace fossil called Ophiomorpha, a combined dwelling
and feeding burrow of a callianassid shrimp from the Middle Eocene
Ione Formation, Ione Basin, Amador County, California.
Images
Of "Days Of Discovery" In The Ione Basin, California
Click on the image for
a larger view. Here is a late afternoon view to the Discovery
Site in the Ione Basin, Amador County, California--the specific
locality, marked by the blue backpack at lower right, where I
first found fossil plants in the Middle Eocene Ione Formation
on July 21, 1991. This is pretty high up in the local Ione Formation
geologic section. Take a look at the pale-brown, brush covered
slopes along the skyline. The overlying Upper Oligocene to Lower
Miocene Valley Springs Formation begins at the dramatic, distinctive
vegetation break along that hillside in the distance--the exact
geologic contact between the Valley Springs above and the Ione
Formation below lies at the obvious break between the green manzanita
brush below and the pale-brown, grass-covered, tree-studded slope
above; rocks above the patch of green manzanita, to the skyline,
belong to the Valley Springs Formation.
What follows is a series
of images depicting several of the original fossil leaf localities
I discovered in the Ione Basin during my "Days Of Discovery"--
my periodic explorations--in the Middle Eocene Ione Formation.
Image #1--The Discovery Site, the exact locality
where I first found fossil plants in the Middle Eocene Ione Formation,
Ione Basin, on July 21, 1991.
Image #2--An image of a second major fossil
leaf horizon in the Ione Basin, a locality I discovered on June
19, 1992.
Image #3--My third major discovery of a prolific
fossil leaf-bearing locality in the Ione Basin--a site I found
on May 4, 1993.
Image #4--A scenic vista from an especially
fossiliferous locality in the Middle Eocene Ione Formation, Ione
Basin; found during a trek in the mid 1990s.
Image #5--An image showing where I found in
the mid 1990s the first convincing, undeniable fossil palm reported
from the Middle Eocene Ione Formation of the Ione Basin--a specimen
I donated to the University California Museum Of Paleontology
in Berkeley.
Image #6--One of the amazingly prolific fossil
leaf localities I discovered in the Middle Eocene Ione Formation
of the Ione Basin during one of my treks in the mid-1990s.
Image #7--An image a fossil leaf locality
I discovered in 1992 in the Middle Eocene Ione Formation, Ione
Basin--a specific horizon later known to paleobotanists as Lygodium
Gulch.
Image #8--An especially productive fossil
leaf locality I discovered during the mid 1990s in the Middle
Eocene Ione Formation of the Ione Basin; a locality that has
never been scientifically quarried due to its occurrence on rather
environmentally sensitive property.
Image #9--A major fossil leaf horizon I discovered
in the Middle Eocene Ione Formation of the Ione Basin during
the mid-1990s. Although the site has never been quarried scientifically,
I did donate all of the specimens I found there, during several
successive visits, to the archival paleobotany collections at
the University California Museum Of Paleontology in Berkeley.
Image #10--A view of a major fossil leaf horizon
I discovered during one of my hikes in the Middle Eocene Ione
Formation, Ione Basin, in the mid-1990s.
Image #11--One of the better-exposed fossil
leaf-bearing sections in the Middle Eocene Ione Formation, Ione
Basin--a place I found during a hike in the mid-1990s. It's a
site that should be scientifically quarried--though it probably
never will be due to its occurrence on property that is environmentally
sensitive.
Image #12--One of the all-time great fossil
leaf-bearing horizons in the Middle Eocene Ione Formation, Ione
Basin; I discovered it during a hike sometime in 1992. It is
an extension of the same ultra-prolific horizon that produces
an abundance of plants at a famous locality now known as Lygodium
Gulch.
Images
From Field Trip To Ione Basin--October 19, 1999
Click on the image for
a larger view. This is a view to a very productive fossil leaf
locality in the Middle Eocene Ione Formation--a photograph snapped
on October 19, 1999, during a field trip to the Ione Basin with
my late father (red plaid shirt, an Engineering Geologist) and
paleobotanists Dr. Diane Erwin (blue-jeans); Collections Manager
of Fossil Plants at the University California Museum Of Paleontology
in Berkeley) and Howard Schorn (retired Collections Manager of
Fossil Plants at UCMP).
I had discovered this site
during one of my excursions to the Ione Basin in the mid 1990s.
After I'd donated numerous fossils from the Ione Basin to the
archival paleobotany collections at UCMP in late 1998, Howard
Schorn and Dr. Erwin wanted to field-check, personally, several
of the specific fossil sites I had discovered. And so we arranged
a day's visit to the Ione Basin for October 19, 1999--Images
from that field trip follow.
Image #1--My
father (an Engineering Geologist) and paleobotanists Howard Schorn
and Dr. Diane Erwin visit a major fossil leaf-bearing horizon
in the Middle Eocene Ione Formtion, Ione Basin. Photograph taken
October 19, 1999.
Image #2--Paleobotanists
Howard Schorn and Dr. Diane Erwin examine on a map one of the
fossil localities I had plotted in the Middle Eocene Ione Formation,
Ione Basin. Photograph taken October 19,
1999.
Image #3--Paleobotanists
Howard Schorn and Dr. Diane Erwin examine on a map one of the
fossil localities I had plotted in the Middle Eocene Ione Formation,
Ione Basin. Photograph taken October 19,
1999.
Image #4--My father (an Engineeering Geologist)
and paleobotanists Dr. Diane Erwin and Howard Schorn at a dramatic
overview in the Ione Basin. Photograph
taken October 19, 1999.
Image #5--A dramatic, scenic overview in the
Ione Basin, western foothills of the Sierra Nevada, Amador County,
California. Photograph taken October 19,
1999.
Image #6--My father (an Engineerin Geologist)
and paleobotanists Howard Schorn and Dr. Diane Erwin at the Discovery
Site--the specific locality where I had first found fossil plants
in the Ione Basin on July 21, 1991. Photograph
taken October 19, 1999.
Image #7--My father (an Engineering Geologist)
and paleobotanists Dr. Diane Erwin and Howard Schorn examine
the rich fossil-bearing outcrops at what later became known as
Lygodium Gulch. During the summer of 2002, Howard Schorn and
I opened up a major quarry here in order to gather the first
formal, systematic, scientific collection of fossil leaves from
the Middle Eocene Ione Formation of the Ione Basin, California.
Photograph taken October 19, 1999.
Image #8--Paleobotanist Dr. Diane Erwin collecting
fossil plants from perhaps the most prolific locality in the
Middle Eocene Ione Formation of the Ione Basin, California. I
discovered this particular site during one of my excursions to
the Ione Basin in 1992. It has since become known to paleobotanists
as "Lygodium Gulch," named after the rather common
to abundant remains of a fossil climbing fern found there, Lygodium
kaulfussi, whose closest modern equivalent is Lygodium
palmatum now native to the southeastern and eastern United
States; it has been recorded from Mississippi, Alabama and Georgia
north to New England--the only known locality west of the Rocky
Mountains to yield climbing fern fossils now housed in a museum.
Photograph taken October 19, 1999.
Image #9--A photograph of famous Loreta's
restaurant in the historic town of Ione. This is a suppemental
image, snapped on November 1, 2002. After our visits to fossil
localities in the Ione Basin on October 19, 1999, we all headed
to Loreta's for a late-afternoon snack of lemon pie.
Images
From Field Trip To Ione Basin--August 19, 2000
Click on the image for
a larger view. This is a photograph snapped on August 19, 2000,
at famous Lygodium Gulch in the Middle Eocene Ione Formation,
Ione Basin. The late paleobotanist Dr. Jack A. Wolfe is kneeling,
examining a fossil leaf specimen before he wraps it in newspaper
for safe transport to the archival paleobotanical collections
at the University California Museum Of Paleontology in Berkeley.
My late father, an Engineering Geologist, looks on in the blue
plaid shirt behind Dr. Wolfe, while paleobotanist Howard Schorn
(with the walking stick in hand), gazes to the scenic countryside
all around us.
To help professional paleobotanists
prepare for their proposed project to study the numerous Eocene
fossil floras of the Sierra Nevada region, to determine the paleoelevations
and paleoclimate of the ancestral Sierra Nevada roughly 50 to
45 million years ago, my father (an Engineering Geologist) and
I took paleobotanists Howard Schorn, Dr. Jack A. Wolfe and Dr.
Bruce Tiffney on a day's tour of some significant fossil leaf
localities in the Ione Basin. Images from the visit follow.
Image
#1--Paleobotanists
Dr. Jack A. Wolfe and Howard Schorn, and my father (an Engineering
Geologist), visit famous fossil leaf locality, Lygodium Gulch
in the Middle Eocene Ione Formation, Ione Basin. Image taken
August 19, 2000.
Image
#2--Paleobotanist
Howard Schorn examines a fossil plant specimen at the famous
"Lygodium Gulch" locality in the Middle Eocene Ione
Formation, while paleobotanist Dr. Jack A. Wolfe wraps specimens
in newspaper for safe transport to the archival paleobotanical
collections at the University California Museum Of Paleontology
in Berkeley. Image taken August 19, 2000.
Image
#3--Paleobotanist
Howard Schorn examines a fossil plant specimen at the famous
"Lygodium Gulch" locality in the Middle Eocene Ione
Formation, while paleobotanist Dr. Jack A. Wolfe refers to his
field notes; my father (an Engineering Geologist) observes the
proceedings. Image taken August 19, 2000.
Image
#4--A photograph
of four scientists at the famous Lygodium Gulch locality in the
Middle Eocene Ione Formation, Ione Basin, western foothills of
the Sierra Nevada, California: Paleobotanist Dr. Bruce Tiffney
(professor at the University of California Santa Barbara) splits
a chunk of shale in search of fossil plants; paleobotanist Dr.
Jack A. Wolfe (retired member of the United States Geological
Survey) examines a fossil leaf specimen; paleobotanist Howard
Schorn looks at a fossil leaf; my father (an Engineering Geologist)
observes the situation. Image taken August 19, 2000.
Images
Of Field Trip To Ione Basin--July 27-August 2, 2002
Click on the image for
a larger view. Paleobotanist Howard Schorn (retired Collections
Manager Of Fossil Plants at the University California Museum
Of Paleontology in Berkeley) supervises a backhoe operator at
a famous fossil plant locality, Lygodium Gulch. The backhoe operator
is exposing for ease of collecting a trench at the primary fossil
horizon. Image taken on July 30, 2002.
A proposed National Science
Foundation grant to study the Eocene fossil floras of California's
Sierra Nevada region had finally been approved. This was unexpected,
but wondrously exciting news, indeed. Only a year earlier, I
had learned that the NSF project had been denied by the "powers
that be," as it were. Now, Howard Scborn invited me to accompany
him to Lygodium Gulch, the most prolific and easily accessible
fossil plant locality in the Ione Basin, to spend a week collecting
leaf fossils for the NSF study. Images from the field trip follow.
Image
#1--Paleobotanist
Howard Schorn (retired Collections Manager Of Fossil Plants at
the University California Museum Of Paleontology in Berkeley)
supervises a backhoe operator at a famous fossil plant locality,
Lygodium Gulch, in the Middle Eocene Ione Formation, Ione Basin.
Image taken on July 30, 2002.
Image
#2--Two images
of paleobotanist Howard Schorn at Lygodium Gulch, Middle Eocene
Ione Formation, Ione Basin, California. At this point, we've
yet to call in the backhoe operator to help us more efficiently
expose the supremely fossiliferous horizon here. Image taken
on July 28, 2002.
Image
#3--Paleobotanist
Howard Schorn greets the backhoe operator at Lygodium Gulch,
Ione Basin, California. This image was snapped during the late
morning of July 30, 2002.
Image
#4--Paleobotanist
Howard Schorn supervises the "first crunch" of the
backhoe at wondrously fossiliferous Lygodium Gulch, Middle Eocene
Ione Formation, Ione Basin, California. Our equipment operator
used superior expertise to entrench the leaf-bearing layer, ripping
up plentiful huge blocks of potentially fossiliferous shales
for us to split apart. Image snapped on July 30, 2002.
Image
#5--The backhoe
plunges with dynamic power and efficiency into the highly fossiliferous,
leaf-bearing shales of the Middle Eocene Ione Formation at Lygodium
Gulch, Ione Basin, California. Image snapped on July 30. 2002.
Image
#6--Our backhoe
operator scoops up great quantities of fossiliferous, plant-bearing
shale at Lygodium Gulch, Middle Eocene Ione Formation, western
foothills of the Sierra Nevada, Ione Basin, Amador County, California.
Image snapped on July 30, 2002.
Image
#7--Paleobotanist
Howard Schorn looks on as our backhoe operator gears up for another
plunge into the ever-expanding fossil trench, Middle Eocene Ione
Formation, Ione Basin, California. Image snapped on July 30,
2002.
Image
#8--Paleobotanist
Howard Schorn stands in the newly dug fossil quarry in the Middle
Eocene Ione Formation, western foothills of the Sierra Nevada,
Amador County, California--our backhoe operator, with great skill
and expertise, entrenched the fossiliferous horizon, carefully
dumping in the process enormous quantities of large blocks of
leaf-bearing shales all around the perimeter of the dig. Image
snapped on July 30, 2002.
Image
#9--A closeup
of the alternating fossiliferous shales and sandstones exposed
at the fossil quarry at famous Lygodium Gulch, in the Middle
Eocene Ione Formation; the best fossil leaves occur in the thin-bedded,
brilliant white, feldspar and biotite-rich shales which are here
interbedded with coarser-brained reddish brown sandstones. Image
snapped on July 30, 2002.
Image
#10--The aftermath
of our week's collecting expedition. In the distance, paleobotanist
Howard Schorn is packing away fossil leaf specimens, readying
them for transport back to the archival paleobotanical collections
at the University California Museum Of Paleontology in Berkeley.
Image was snapped in the mid afternoon of August 1, 2002--our
last day of digging at Lygodium Gulch in the Middle Eocene Ione
Formation during our week's visit to the western foothills of
the Sierra Nevada, Amador County, California.
Images
Of Field Trip To Ione Basin--October 14, 2002
Click on the image for
a larger view. This is a classic, scenically striking geologic
contact in the Middle Eocene Ione Formation, western foothills
of the Sierra Nevada, Ione Basin, Amador County, California.
The whitish layer in the exposure is a massive, coarse sandstone
that represents turbulent floodplain conditions some 48 million
years ago during Eocene geologic times. Above that massive white
sandstone is a more thinly bedded deposit of feldspar-rich reddish-brown
sandstones and shales; probably this too was deposited by rivers
that periodically flooded their banks, but the mineral contact
of the shales and sandstones is dramatically different than the
essentially pure quartz content of the massive white sandstone
below. Picture taken October 14, 2002.
I had long-wanted to get
father, an Engineering Geologist, out to Lygodium Gulch, to observe
first-hand the stratigraphy and geology of the area after paleobotanist
Howard Schorn and I had quarried the fossil locality earlier
that year, in late July and early August of 2002. Also, I wanted
to take some photographs of the local flora. Images from that
October 14, 2002, visit follow.
Image #1--A classic, scenically striking geologic
contact in the Middle Eocene Ione Formation, western foothills
of the Sierra Nevada, Ione Basin, Amador County, California.
Image taken October 14, 2002.
Image #2-- A typical scrub oak of the Quercus
berberidifolia variety growing near the Lygodium Gulch fossil
leaf locality, on the harsh, acidic alkaline soils of the Middle
Eocene Ione Formation. Image taken on October 14, 2002.
Image #3--A close-up of the distinctive foliage
and acorns of Quercus berberidifolia, a small, brush-sized
variety of scrub oak growing near the Lygodium Gulch fossil leaf
locality, on the harsh, acidic alkaline soils of the Middle Eocene
Ione Formation. Image taken October 14, 2002.
Image #4--A nice specimen of a Digger Pine
(also called the Foothill Pine), Pinus sabiniana near
the Lygodium Gulch fossil leaf locality in the Middle Eocene
Ione Formation, Amador County, California. Image snapped on October
14, 2002.
Image #5--A brushy clump of Sticky white-leaf
manzanita, Arctostaphylos viscida, observed near the famous
Lygodium Gulch fossil leaf locality in the Middle Eocene Ione
Formation. Image snapped on October 14. 2002.
Image #6--A typical, distinctive clump of
the rare, protected Ione manzanita, Arctostaphylos myrtifolia
observed near the famous Lygodium Gulch fossil leaf locality
in the Middle Eocene Ione Formation. Image snapped on October
14, 2002.
Image #7--Several low-lying, distinctive dark-green
clumps of the rare, protected Ione manzanita, Arctostaphylos
myrtifolia observed near the famous Lygodium Gulch fossil
leaf locality in the Middle Eocene Ione Formation. Image snapped
on October 14, 2002.
Image #8--My father, an Engineering Geologist,
examines a fossil leaf specimen at the Lydodium Gulch quarry
in the Middle Eocene Ione Formation, western foothills of the
Sierra Nevada, Amador County, California. Image snapped on October
14, 2002.
Images
Of Field Trip To Ione Basin--October 22, 2002
Click on the image for
a larger picture. Close-up of the foliage of the rare, protected
Ione manzanita, Arctostaphylos myrtifolia, observed near
the famous Lygodium Gulch fossil leaf locality in the Middle
Eocene Ione Formation. The Ione manzanita grows nowhere else
on Earth in the wild, save on the extraordinarily harsh, acidic
soils weathered from the Eocene Ione Formation within the unique
Ione Chaparral botanic association, Ione Basin, Amador County,
California. Image snapped on October 22, 2002.
In prepartion for a field
trip with paleobotanist Howard Schorn and student crews from
a Commuity College and a university, sceduled for October 25-27,
2002, I wanted to return to Lygodium Gulch to clear entangled
brush from the path to the fossil locality. Also, I wanted to
snap some photographs of the two dominant, local species of manzanitas.
Images from that visit on October 22, 2002, follow.
Image #1--Close-up of the foliage of the rare,
protected Ione manzanita, Arctostaphylos myrtifolia observed
near the famous Lygodium Gulch fossil leaf locality in the Middle
Eocene Ione Formation. Image taken October 22, 2002.
Image #2-- An overview of the two major varieties
of manzanita that inhabit the Ione Chaparral, observed near the
famous Lygodium Gulch fossil leaf locality in the Middle Eocene
Ione Formation. Ione Basin, western foothills of the Sierra Nevada,
Amador County, California: the rare, protected Ione manzanita
and the Sticky white-leaf manzanita. Image taken on October 22,
2002.
Image #3--Bushy shrubs of the Sticky white-leaf
manzanita, Arctostaphylos viscida, observed near Lygodium
Gulch, one of the great fossil leaf localities in the Middle
Eocene Ione Formation, western foothills of the Sierra Nevada,
Ione Basin, Amador County, California. Image taken October 22,
2002.
Image #4-Another view of the dramatic, striking
geologic contact in the Middle Eocene Ione Formation, seen in
the previous image--here, brilliant white, massive fluvial (river-deposited)
sandstones (mined for their commercial grade content of silica
elsewhere in the Ione Basin) underlie thinly bedded reddish-brown
shales and sandtones that contain a higher percentage of biotite
and feldspar than the white sandstones below. Image snapped on
October 22, 2002.
Image #5--A look at the two dominant varieties
of manzanita in the Ione Basin, western foothills of the Sierra
Nevada, Amador County, California--as observed in the vicinity
of Lygodium Gulch, one of the most significant fossil leaf localities
in all of California. Image snapped on October 22. 2002.
Images
Of Field Trip To Ione Basin--October 25-27, 2002
Click on the image for
a larger view. Students from a Community College and a university
help collect fossil leaves from the Middle Eocene Ione Formation
at famous Lygodium Gulch during a weekend field trip to the Ione
Basin, western foothills of the Sierra Nevada, Amador County,
California. The combined student forces helped increase the numbers
of fossil leaves available for a fascinating paleobotanical project
sponsored by the National Science Foundation--to study the Eocene
floras of the Sierra Nevada district, in order to determine the
paleoelevations and paleoclimate of the ancestral Eocene Sierra
Nevada. Image taken on October 27, 2002.
Images from the field trip
with the combined College-university collecting crews on October
25-27, 2002, follow.
Image
#1--Students from
a Community College and a university help collect fossil leaves
from the Middle Eocene Ione Formation at famous Lygodium Gulch
during a weekend field trip to the Ione Basin, western foothills
of the Sierra Nevada, Amador County, California. Image taken
October 27, 2002.
Image
#2--A backhoe
operator expands the fossil trench at famous Lydodium Gulch,
in the Middle Eocene Ione Formation, Ione Basin, western foothills
of the Sierra Nevada, Amador County, California.Nevada--all in
preparation for a joint field trip with student collecting crews
from a Community College and a university on October 26 and 27,
2002. Image taken on October 25, 2002.
Image
#3--A backhoe
operator, hired by paleobotanist Howard Schorn, expands the fossil
trench at famous Lydodium Gulch, in the Middle Eocene Ione Formation,
Ione Basin, western foothills of the Sierra Nevada, Amador County,
California.Nevada--all in preparation for a joint field trip
with student collecting crews from a Community College and a
university. Image taken October 25, 2002.
Image
#4--The backhoe
in action, expanding dramatically and efficiently the fossil
trench at famous Lydodium Gulch, in the Middle Eocene Ione Formation,
Ione Basin, western foothills of the Sierra Nevada, Amador County,
California.Nevada--all in preparation for a joint field trip
with student collecting crews from a Community College and a
university on October 26 and 27, 2002. Image taken on October
25, 2002.
Image
#5--The collecting
crews arrive. Paleobotanist Howard Schorn (right side of image)
directs professors and their students from a Community College
and a university to the staging area near famous fossil leaf-yielding
locality, Lygodium Gulch, Ione Basin, western foothills of the
Sierra Nevada, Amador County, California. Image taken October
26, 2002.
Image
#6--Students
from a Community College and a university, along with their respective
professors, assemble at Lygodium Gulch, a classic fossil leaf-bearing
locality in the Ione Basin, western foothills of the Sierra Nevada,
Amador County, California. Image taken October 26, 2002.
Image
#7--Students
from a Community College and a university, along with their respective
professors, assemble at the fossil trench at Lygodium Gulch,
a classic fossil leaf-bearing locality in the Ione Basin, western
foothills of the Sierra Nevada, Amador County, California. Image
taken October 26, 2002.
Image
#8--Students
from a Community College and a university, along with their respective
professors, get down to business at Lygodium Gulch, one of the
great fossil leaf-bearing localities in the Ione Basin, western
foothills of the Sierra Nevada, Amador County, California. Image
snapped October 26, 2002.
Image
#9--A professor
from a university, along with a student and a playful youngster,
insects a piece of shale at Lygodium Gulch, one of the great
fossil leaf-bearing localities in the Ione Basin, western foothills
of the Sierra Nevada, Amador County, California. Image snapped
October 26, 2002.
Image
#10--Paleobotanist
Howard Schorn, retired Collections Manager Of Fossil Plants at
the University California Museum Of Paleontology, observes an
eager college student down in the fossil trench at Lygodium Gulch,
one of the great fossil leaf-bearing localities in the Ione Basin,
western foothills of the Sierra Nevada, Amador County, California.
Image snapped October 26, 2002.
Image
#11--Students
and their professors from a Community College and a university
spread out at famous Lygodium Gulch, one the truly great fossil
leaf-bearing localities in the Ione Basin, western foothills
of the Sierra Nevada, Amador County, California. Image snapped
October 26, 2002.
Image
#12--Students
and their professors from a Community College and a university
collect fossil plants at famous Lygodium Gulch, one the truly
great fossil leaf-bearing localities in the Ione Basin, western
foothills of the Sierra Nevada, Amador County, California. Image
snapped October 26, 2002.
Image
#13--Students
from a Community College and a university begin to wrap for safe
transport the abundant fossil plants they had found during the
final day of the dig at famous Lygodium Gulch, one the truly
great fossil leaf-bearing localities in the Ione Basin, western
foothills of the Sierra Nevada, Amador County, California. Image
snapped October 27, 2002.
Images
Of Field Trip To Ione Basin--June 2-3, 2003
Click on the image for
a larger picture. Paleobotanist Howard Schorn, retired Collections
Manager Of Fossil Plants at the University California Museum
Of Paleontology in Berkeley, and geologist Robinson Cecil observe
significant outcrops of the Middle Eocene Ione Formation in the
Ione Basin, western foothills of the Sierra Nevada, Amador County,
California. Image snapped on June 3, 2003.
Howard had invited me on
the field trip to help Robinson, then a geology student at the
University Of Arizona in Tucson, familiarize herself with some
leaf-bearing Eocene geologic sections she planned to measure
for a National Science Foundation project (co-led by the late
paleobotanist Dr. Jack A. Wolfe) to determine the paleoelevations
and paleoclimate of the Sierra Nevada during Eocene geologic
times, roughly 50 to 45 million years ago.Images from that visit on June 3,
2003, follow.
Image
#1--Paleobotanist
Howard Schorn, retired Collections Manager Of Fossil Plants at
the University California Museum Of Paleontology in Berkeley,
and geologist Robinson Cecil observe significant outcrops of
the Middle Eocene Ione Formation in the Ione Basin, western foothills
of the Sierra Nevada, Amador County, California. Image snapped
on June 3, 2003.
Image
#2--Paleobotanist
Howard Schorn and geologist Robinson Cecil examine outcrops at
the Discovery Site (the locality where I first found fossil leaves
in the Ione Basin, on July 21, 1991), Middle Eocene Ione Formation,
western foothills of the Sierra Nevada, Amador County, California.
Image taken on June 3, 2003.
Image
#3--Paleobotanist
Howard Schorn, retired Collections Manager Of Fossil Plants at
the University California Museum Of Paleontology in Berkeley,
and geologist Robinson Cecil examine outcrops of the Middle Eocene
Ione Formation, western foothills of the Sierra Nevada, Amador
County, California. Image taken June 3, 2003.
Image
#4--Two well-exposed
and prominent rhyolite volcanic "plugs" in the Lower
Miocene Valley Springs Formation, Ione Basin, western foothills
of the Sierra Nevada, Amador County, California. Image snapped
on June 3, 2003.
Image
#5--Geologist
Robinson Cecil and paleobotanist Howard Schorn study the fossil
quarry at Lygodium Gulch in the Middle Eocene Ione Formation,
Ione Basin, western foothills of the Sierra Nevada, Amador County,
California. Image snapped on June 3, 2003.
Images
Of Field Trip To Ione Basin--March 8, 2004
Click on the image for
a larger picture. Close-up of pinkish flowers on the Sticky white-leaf
manzanita, Arctostaphylos viscida, growing in the vicinity
of Lygodium Gulch, a classic fossil leaf locality in the Middle
Eocene Ione Formation, Ione Basin, western foothills of the Sierra
Nevada, Amador County, California. Image snapped on March 8,
2004.
In early March, 2004, I
had heard news reports that the manzanita blooms in the western
foothills of the Sierra Nevada were especially abundant. That
was quite an enticement all by itself, of course. Also, it was
undeniably obvious that I had not visited the Ione Basin in roughly
9 months, not since the fabulous field trip on June 3, 2003,
with paleobotanist Howard Schorn and geologist Robinson Cecil.
Needless to report, I was itching to return to the Ione Basin.
For my day's visit on March 8, 2004, I planned to document not
only the manzanita blooms in the vicinity of famous Lygodium
Gulch, probably the most prolific and accessible of the great
fossil leaf localities in the Middle Eocene Ione Formation of
the Ione Basin, but also a few of the other fossiliferous sites
in the immediate area, as well.Images from that visit on March 8, 2004, follow.
Image
#1--Close-up of pinkish
flowers on the Sticky white-leaf manzanita, Arctostaphylos
viscida, growing in the vicinity of Lygodium Gulch, a classic
fossil leaf locality in the Middle Eocene Ione Formation, Ione
Basin, western foothills of the Sierra Nevada, Amador County,
California. . Image snapped on March 8, 2004.
Image
#2--A close-up
of white flowers and leaves on the Sticky white-leaf manzanita,
Arctostaphylos viscida, growing in the vicinity of Lygodium
Gulch, a classic fossil leaf locality in the Middle Eocene Ione
Formation, Ione Basin, western foothills of the Sierra Nevada,
Amador County, California. Image taken on March 8, 2004.
Image
#3--Blooms
and foliage on the rare and protected Ione manzanita, Arctostaphylos
myrtifolia, which grows nowhere else in the wild on Earth,
except on the harsh, acidic soils developed in the Middle Eocene
Ione Formation of the Ione Basin, California. Image taken March
8, 2004.
Image
#4--Close-up
of blooms on the rare and protected Ione manzanita, Arctostaphylos
myrtifolia, which grows nowhere else in the wild on Earth,
except on the harsh, acidic soils developed in the Ione Formation
of the Ione Basin, California. Image snapped on March 8, 2004.
Image
#5--A close-up
of blooms on the Sticky white-leaf manzanita, Arctostaphylos
viscida, one of the two primary varieties of manzania that
inhabits the Ione Chaparral (the other is the rare and protected
Ione manzanita, Arctostaphylos myrtifolia)--a unique botanic
association of plantswhich grows nowhere else in the
wild on Earth, except on the harsh, acidic soils developed in
the Ione Formation of the Ione Basin, California. Image snapped
on March 8, 2004.
Image
#6--A close-up
of blooms and foliage on the Sticky white-leaf manzanita, Arctostaphylos
viscida, one of the two primary varieties of manzania that
inhabits the Ione Chaparral (the other is the rare and protected
Ione manzanita, Arctostaphylos myrtifolia)--a unique botanic
association of plantswhich grows nowhere else in the
wild on Earth, except on the harsh, acidic soils developed in
the Ione Formation of the Ione Basin, California. Image snapped
on March 8, 2004.
Image
#7--One of
many brilliant blue ponds in the Ione Basin, western foothills
of the Sierra Nevada, Amador County, California. This one lies
in a brilliant white, fluviatile (river-deposited), silica-rich
sandstone of the Middle Eocene Ione Formation, situated in the
vicinity of Lygodium Gulch. Image snapped on March 8, 2004.
Image
#8--Two views
of the same prolific fossil horizon in the Middle Eocene Ione
Formation, Ione Basin, western foothills of the Sierra Nevada,
Amador County, California. Image snapped on March 8, 2004.
Image
#9--A view
to a fossil leaf horizon in the Middle Eocene Ione Formation,
Ione Basin, western foothills of the Sierra Nevada, Amador County,
California. Image snapped on March 8, 2004.
Image
#10--A view
to a fossil leaf horizon in the Middle Eocene Ione Formation,
Ione Basin, western foothills of the Sierra Nevada, Amador County,
California. Image snapped on March 8, 2004.
Images
Of Field Trip To Ione Basin--March 22, 2004
Click on the image for
a larger picture. Exposures of the Middle Eocene Ione Formation
in the vicinity of the Discovery Site--so-named because that's
where I first found fossil plants in the Ione Basin on July 21,
1991. Grayish-white, unfossiliferous carbonaceous mudstones outcrop
below plant-bearing reddish-brown sandstones (roughly middle
of picture). At upper left to upper-center, the grass-covered,
tree-studded slopes belong to overlying Lower Miocene Valley
Springs Formation. Image taken on March 11, 2004.
After my enjoyable day's
return to the Ione Basin on May 8, 2004, while the weather still
held, I wanted to revisit the vicinity of The Discovery site,
to document outcrops of the Middle Eocene Ione Formation. Several
of the exposures out that way yielded common to abundant fossil
leaves--fossilferous horizons I wanted to examine and photograph,
naturally--but, in addition, I also had in mind to document with
a camera a number of the representive rock lithologies of the
Middle Eocene Ione Formation. Images from that visit on March
11, 2004, follow.
Image
#1--Grayish-white,
unfossiliferous carbonaceous mudstones outcrop below plant-bearing
reddish-brown sandstones in the Middle Eocene Ione Formation,
Ione Basin. Image taken on March 11, 2004.
Image
#2--A nice
outcropping of conglomerate in the Ione Formation. Local gravel
beds such as these in the Ione Basin resemble the world-famous
auriferous, gold-bearing gravels that occur higher up the western
slopes of the Sierra Nevada, in the neighborhood of Grass Valley/Nevada
City. Image taken on March 11, 2004.
Image
#3--A prolific
fossil leaf locality in the Ione Formation--a specific paleobotanical
site that has not yet been scientifically quarried, primarily
because of its relative inaccessibility and its occurrence on
environmentally sensitive terrain. Image taken on March 11, 2004.
Image
#4--Close-up
of blooms on the wildflower called Indian Paintbrush., growing
on exposures of the Middle Eocene Ione Formation, Ione Basin.
Image snapped on March 11, 2004.
Image
#5--An outcrop
that demonstrates to great advantage the clay-rich properties
of the Ione Formation. Elsewhere in the Ione Basin, several beds
in the Ione Formation are mined for their commercial-grade quantities
of kaolinite clay. Image taken on March 11, 2004.
Image
#6--A characteristic
outcrop of rather massive sandstones in the Middle Eocene Ione
Formation, Ione Basin, observed in the neighborhood of The Discovery
site--so-named because that's the specific locality where I first
found fossil plants in the Ione Basin back on July 21, 1991.
This particular geologic exposure is unfossiliferous, but does
show quite nicely a common kind of rock lithology one often encounters
in the Ione Formation of the Ione Basin. Image taken on March
11, 2004.
Image
#7--One of
many peaceful, pastoral ponds, privately owned, that can be found
throughout the Middle Eocene Ione Formation of the Ione Basin.
Image taken on March 11, 2004.
Image
#8--An exposure
of one of the most prolific leaf-bearing localities in all the
Middle Eocene Ione Formation of the Ione Basin. Image taken
on March 11, 2004.
Image
#9--A foot-long
geology rock hammer lends perspective to a distinctive and typical
outcropping of the Middle Eocene Ione Formation, Ione Basin.
Image taken on March 11, 2004.
Image
#10--A view
eastward from the Middle Eocene Ione Formation, Ione Basin, Amador
County, to the western foothills of the Sierra Nevada. Image
taken on March 11, 2004.
Image
#11--A highly
fossiliferous section of the Middle Eocene Ione Formation, Ione
Basin; here occur many well-preserved fossil leaves in grayish-white
mudstones and in reddish-brown shales. Several large blocks of
shale and mudstone here yielded whole, complete leaves plastered
along the bedding planes--specimens that now reside in the archival
paleobotany collections at the University California Museum Of
Paleontology in Berkeley. Image taken on March 11, 2004.
Image
#12--One of
many peaceful, pastoral, private ponds that can be found throughout
the Middle Eocene Ione Formation of the Ione Basin. The owners
of this property come here on occasion for family outings. Image
taken on March 11, 2004.
Links
To The Eocene Epoch Of The Cenozoic Era
It's The Same Division
Of Geologic Time During Which The Ione Formation Accumulated
