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| Several participants in the paleobotanical dig prepare to hike to the fossil plant locality in the Middle Eocene auriferous gravels in the western foothills of the Sierra Nevada, Nevada County, California--including group leader geologist David Lawler, seen standing in the back of the pick-up truck with blue shirt and beige hat. After meeting at Dennys Restaurant in Grass Valley by 9:00 in the morning, members of the Far West Geoscience Foundation headed east in caravan style several miles to Sailor Flat, an abandoned hydraulic mine that yielded vast quantities of gold during the mid to late 1800s. At a convenient parking area above the old gold diggings, we consolidated forces and piled into several four-wheel drive vehicles for the final assault, a rough, sharply descending rocky ride over a primitive jeep trail to the bottom of the great hydraulic pit. We were after an unusually thick bed of the world-famous, fossiliferous chocolate-colored shales that are interbedded with the coarse, fluviatile (river-deposited) auriferous gravels--pebble to boulder-sized debris left behind some 50 to 40 million years ago by the Tertiary Yuba River Channel. In swampy, ponded areas along that ancient river channel, quiet-water lacustrine (lake) shales developed on the Eocene flood-plains and helped preserve an astounding variety of fossilized vegetation--nearly 70 species of ancient plants have been described from what paleobotanists call the Chalk Bluffs Flora, or those associations of fossil plants found in the Middle Eocene auriferous gravels exposed by hydraulic methods during the Gold Rush days of the mid to late 1800s--an awe-inspiring fossil flora whose overall composition resembles a modern subtropical Mexican Elm-Liquidamber forest at the foot of Mount Orizaba in Vera Cruz, Mexico. There are also similarities to such modern subtropical forests as those found along the Rio Moctezuma at Tomazunchale, Mexico; to the Liquidamber-Oak and Mexican Elm forests near Coban, Guatemala; and to the Liquidamber forests in the eastern Sierra Madre west of Tomazunchale, Mexico, and in the state of Morelos, Mexico. |
| Dr. Diane Erwin (left), Collections Manager of Fossil Plants at the University California Museum of Paleontology, and Cathy Zyskowski collect fossil leaves from Middle Eocene (roughly 48 million years old) "chocolate shales" at the Sailor Flat Hydraulic Mine in Nevada County, California, several miles east of Grass Valley/Nevada City; all significant fossil specimens went to the archival paleobotanical collections at the University California Museum of Paleontology. The fossil locality presently lies on private property. Permission to collect here was kindly granted by the owners of the Sailor Flat Hydraulic Mine. |
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Howard Schorn (retired Collections Manager of fossil plants at the UC Museum of Paleontology in Berkeley, California)--co-leader of the Far West Geoscience paleobotany field trip to the Sailor Flat hydraulic gold mine discussed at this Web page--has co-authored a great reference volume, entitled A Computer-Assisted Annotated Bibliography and Preliminary Survey of Nevada Paleobotany. Open-File Report 94-441B of the United States Geological Survey. For details on obtaining a copy of this comprehensive paleobotanical report, Click Here. Dr. Diane Erwin (Collections Manager Of Fossil Plants at the UC Museum of Paleontology in Berkeley, California) wrote an excellent field trip article for UCMP. It's a visit to the Sierra Nevada in search of fossil plants. Howard Schorn also provides a comprehensive overview of the geology and paleobotany of the Middle Eocene Chalk Bluffs Flora. The late Jack Wolfe (passed away in August, 2005) and Bob Spicer put together an excellent web page devoted to the Climate Leaf Analysis Multivariate Programe (CLAMP). This is how one goes about determining paleoclimates from a sophisticated study of leaf characteristics. For a general overview of the paleobotany and geology of the Sierra Nevada and western Nevada, visit Dr. Constance Millar's Tertiary Vegetation History, which is in PDF format--you'll need an Adobe Acrobat Reader to access the file. Read an interview with paleobotanist Dr. Pigg about her paleobotanical research in the Arizona State University Research magazine. For more paleobotany field trips, try these links: Field Adventures: Florissant (a visit to the famous Late Eocene Florissant Lake Beds locality in Colorado); Field Adventures: Big Cedar Ridge (a visit to the Late Cretaceous Meeteetse Formation in northern Wyoming); Field Adventures: Petrified Forest (a visit to Petrified National Forest in Arizona to search for fossil cycads in the Late Triassic Chinle Formation); Fossil Hunting At Oviatt Creek, Idaho. Dr. Kathryn M. Gregory-Wodzicki of Lamont-Dohery Earth Observatory Columbia University has several of her excellent technical paleobotanical papers available for download in PDF format at her Home Page; you'll need the free version of Adobe's Acrobat Reader to access the files. Dr. R. A. Gastaldo of Colby College, Waterville, Maine, has an excellent online Paleobotany syllabus available at his Notes For A Course In Paleobotany page. And here are some additional paleobotany resources available on the Web: Plant Fossils Of West Virginia; Paleobotanical Section Of The Botanical Society Of America; Castle Rock Fossil Rainforest; Hans' Paleobotany Pages; Paleobotany And Palynology Image Gallery; Florida Museum Of Natural History Paleobotany And Palynology; Boggy's Links To Paleobotany; Paleobotany: The Origin Of Flowering Plants; Paleobotany Laboratory At Weston Observatory; Eocene Amber And Fossil Leaves In Arkansas; Eocene Green River Formation Plants; Science Notes: Summer 1998 (early Eocene paleoclimate studies in Wyoming); Petrified Wood From Western Washington. And here's a link to probably the most comprehensive collection of paleobotany links on the Web: Links For Paleobotanists. |
The most famous hydraulic gold mine in the Sierra Nevada
Smithsonian Magazine: Phenomena, comments & notes
Malakoff Diggins State Historic Park
North Bloomfield And Malakoff Diggins
The Land Of Glittering Dreams
Geoimages
Onsite Adventures: Malakoff
Gold Fever Giant Gold Machines--Hydraulic Mining
Nevada County Gold Online
Nevada County Community Network
The Union: Local Nevada County Newspaper Nevada City/Grass Valley
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| And be sure to visit my other Web Sites: Visit My Pages, where I have all of my other fossils and guitar music Web Pages linked and categorized. |