One of the great Early Cambrian trilobite localities in the western United States can be found in Esmeralda County, Nevada, only a few miles north of Death Valley National Park. It is a place where invertebrate paleontologists have identified a least 12 species of trilobites from a series of terrigenous and carbonate strata mapped as the Lower Cambrian Harkless Formation some 540 million years old. This specific fossil locality, as a matter of fact, has yielded the single largest assemblage of Early Cambrian trilobites yet described from North America. Thus, it is a unique and scientifically invaluable area--accessible to amateurs, by the way--primarily because its fabulous arthropod fauna has already been described by the famous Cambrian trilobite specialist Allison R. (Pete) Palmer, who published his findings in 1964 in United States Geological Survey Professional Paper 483-F, An Unusual Lower Cambrian Trilobite Fauna From Nevada.

Nevertheless, the wonderful arthropod horizon remains a geologically sensitive place. Visitors to the region must respect its fragile nature, understanding that if commercial collecting parties begin to desecrate the stratigraphic integrity of the exposed strata--ripping the fossiliferous rocks from their ancient resting place by mechanized means--officials with the Bureau of Land Management (BLM) will have no recourse but to close the entire district, preventing interested amateur collectors from experiencing the exhilarating rewards of paleontological discovery here; of course, it is not likely that commercial collectors would favor the Gold Point area, anyway, since complete, perfect trilobite specimens are so rarely recovered--a not unexpected situation when dealing with the majority of Early Cambrian fossil localities world-wide. Still, even though the BLM is invariably a patient and tolerant organization, managing millions of acres of public lands with friendly efficiency, the usual good nature of its staff should not be tested to the limit. Commercial collectors must stay away; otherwise, only those with certificates of accreditation will be allowed to keep what they find.

The Gold Point locality lies in the vicinity of Gold Point in Esmeralda County, Nevada--several miles from Mount Dunfee on Slate Ridge, as well--a prominent sedimentary protrusion visible from the fossil site, from whose Late Precambrian rocks paleontologists have identified one of the earliest known assemblages of shelly animals on Earth. The specimens occur in dolomitic carbonates transitional between the Precambrian Reed Dolomite and the Deep Springs Formation and apparently represent varieties of primitive worm tubes occasionally observed in correlative deposits in Mexico and Russia. They were described in an article in the April 1983 edition of Geology, "Precambrian-Cambrian Transition Problem in Western North America: Part 1. Tommotian fauna in the southwestern Great Basin and its implications for the base of the Cambrian System," by Jeffrey F. Mount, Debra A. Gevirtzman and Phillip W. Signor, III--all from the Department of Geology at the University of California at Davis.

What's particularly intriguing about this Late Precambrian site is that the curious worm tubes, measured in a few millimeters in most instances, apparently occur in rocks a full thousand feet lower in the local stratigraphic section than the first appearance of Olenellid trilobites (the Harkless Fm. trilobites are far from the oldest trilobites recognized from the Gold Point district, by the way), extinct arthropod remains that, in a formerly traditional sense, used to define the base of the Cambrian System--now recognized as roughly 540 million years old, not 570 million years ancient, as had been thought for most of the 20th Century.

Even though Mount Dunfee lies rather near the celebrated trilobite beds, the exposed sedimentary material lying between the two areas is not in its original stratigraphic succession; that is to say, one cannot simply hike from the Late Precambrian exposures at Mount Dunfee down slope to the fossil locality and expect to encounter an uninterrupted series of sedimentary layers representing a reliable transition from the oldest periods of deposition to the youngest. The explanation is that potent Earth forces during the Cenozoic Era, roughly 65 million years ago to present, block-faulted vast quantities of intervening strata, creating a jumbled, messy mass of exposed rock deposits which only tedious geologic field mapping can hope to unravel.

Fortunately for folks with paleontological zeal, the disruptive geologic upheavals did not obliterate all of those wonderful Early Cambrian plants and animals that once thrived here in the primordial timelessness of the geologic past. In addition to the prized trilobite exoskeletons--most commonly found as disarticulated, isolated cephalons and thoracic segments--the Gold Point locality also yields a wide assortment of interesting fossil organisms. These include such extinct species as archeocyathids (cup-to conical-shaped creatures whose morphological aspect resembles a cross between a coral and a sponge; for decades, archeocyathids were considered members of a distinct, unique Phylum of animals, but rather recent detailed studies suggest that they are more closely allied with the sponges, and so most paleontologists today consider archeocyathids an extinct variety of sponge.) and salterella (an ice-cream-cone to tusk-shaped specimen roughly 6 to 8 millimeters long; many investigators originally conjectured that salterella represented one of the earliest examples of a cephalopod--sort of a distant ancestor of the ammonite--but more recent analyses have concluded that it was most likely a unique animal deserving of its own zoological category, called Phylum Agmata; salterella, by the way, never survived beyond Early Cambrian times.), in addition to various undescribed annelid trails and arthropod tracks (so-called trace or ichnofossils), algal remains (the well-known Girvanella, a peculiar oval-shaped concretionary specimen characteristic of pure, uncontaminated limetones deposited during latest Early Cambrian times, in what is now the Great Basin) and brachiopod casts and molds.

All of these specimens occur in strata originally mapped as the Lower Cambrian Harkless Formation, although the shales and shaley limestones that yield the trilobites certainly resemble correlative rocks known as the Saline Valley Valley Formation, whose type locality lies over in the Waucoba Spring area in northwestern Death Valley National Park. The informally named Waucoba District used to be an entertaining and productive area to explore for Early Cambrian fossils. Needless to report, the area is now part of the national park system and is completely off-limits to any manner of unauthorized collecting.

The fossiliferous sections at the Gold Point locality are composed of alternating brownish shales, reddish-brown limey shales, orange-brown limestones, greenish-orange shales and dark-gray limestones ( indeed, a rather colorful outcropping of various rock lithologies.). Almost all of the trilobites occur in the thin interbeds of dark-gray limetones that outcrop intermittently along the hillsides.

This is certainly a classic Early Cambrian fossil locality. Even though the vast majority of trilobite specimens will be both fragmental and rather small--most cephalons range from one-quarter to one-half inch (or, 6 to 12 millimeters in metric measurement) in diameter--the sheer abundance and diversity of arthropod remains in the rocks here is truly phenomenal and inspiring. Trilobite varieties identified by Allison R. Palmer include Paedeumias granulata, Wanneria walcottana, Bonnia caperata, Olenoides ssp, Ogyopsis batis, Goldfieldia pacifica, Stephenaspis sp., Stephenaspis avitus, Zacanthopsis sp., Zacanthopsis contractus, Zacanthopsina eperephes, Syspacephalus, and four additional species as yet undescribed.

Credit for discovering this remarkable trilobite-bearing locality goes to two geologists with the United States Geological Survey: J.P. Albers and John H. Stewart. They came across the site during reconnaissance for their geologic field mapping project of Esmeralda County in the early 1960s. In 1960, Palmer examined fossil material Albers and Stewart had collected from the Gold Point site. By all accounts, the extraordinary suite of trilobite specimens immediately "floored him," as it were, and led to his identification of the largest single assemblage of Early Cambrian trilobites yet described from North America.

It should be pointed out that a number of localities in Esmeralda County are currently under formal scientific investigations--hence, their exact position of occurrence cannot be divulged at this time, at least not until they have been described in monographic detail by the paleontologists involved in the investigations. Indeed, I have been sworn to secrecy (under penalty of torture by a trilobite's pygidium) not to reveal at least three other Early Cambrian fossil sites within Esmeralda County--places that yield a plethora of identifiable trilobite specimens, including not a few perfect, intact exoskeletons.

Once at the Gold Point fossil site, most collectors concentrate on the many fine trilobite fossils they find along the more moderately inclined, easily negotiated slopes. This is certainly acceptable behavior, an individual choice, of course, but additional trilobite-yielding horizons can be discovered all along the axis of Gold Point region, within the more rugged topography. Also, a wider variety of fossil remains can be sampled, including: archeocyathids (restricted to thin carbonate horizons interbedded with the shales); worm trails and undetermined arthropod tracks (present locally on greenish quartzitic sandstones and shales; brachiopod molds and casts (usually observed on reddish-brown shales); algal bodies (nodule to concretionary oval specimens in grayish-blue massive limestones); and salterella (seen in orange-brown shaley limestones at irregular intervals--locally quite abundant, forming coquinas in which the carbonate matrix is composed almost entirely of the 6 to 8 millimeter long ice-cream-cone-shaped specimen).

Although none of the non-trilobite specimens is overly abundant here (except for the salterella, which is locally quite prolific), their presence in a least moderate numbers this low in the Lower Cambrian Harkless Formation makes the moderate hiking required to find them a most memorable and rewarding field experience. Of course, not every outcrop in the Gold Point fossil zone will yield something remarkable, but there is definitely enough 540-million-year-old paleontology available to keep even the most jaded explorer in fossil ecstasy.

Here is an important fossil locality that gives us a rare opportunity to look back in geologic time to the surprising diversity and complexity of an Early Cambrian sea, some 540 million years old. That so many biologically successful creatures should have thrived so long ago, and through the eternity of eons, seems to defy all that we believe to be law. Yet, when we hold in our hands the incontrovertible evidence of a creature with eyes in the rocks: a trilobite's eyes that gaze back into our own from ages past, we finally come to realize that those 540 million revolutions around the sun can no longer separate us.

E-mail me with comments or questions at Waucoba4@aol.com