The first paper or publication issued, in which any definite information in regard to the geology of Nevada was given, was that of Messrs. Meek and Engelmann, published in the Proceedings of the Philadelphia Academy of Natural Sciences, for April, 1860. This paper gives the results of the examination by Mr. Meek, of the fossils obtained by Mr. H. Engelmann, who accompanied Capt. J. H. Simpson on his explorations of 1858-59, or what is generally known as “Simpson’s Wagon Road Expedition.” As the full report of this expedition has never been published, we have no other information in regard to the geology of the region traversed by Capt. Simpson’s party than that given in the paper above alluded to. The route followed on this survey was one near the present Overland Stage Road, passing through a region then entirely uninhabited by white men, but now dotted with mining camps and even towns of considerable size—a region which has been proved to contain a large number of argentiferous veins, and where mining operations have been carried on most energetically and extensively during the last two or three years. The localities of fossils mentioned by Messrs. Meek and Engelmann, and included within the limits of Nevada, are as follows: Long. 114° 45´, Lat 39° 45´, near what is now called Egan Cañon, fragments of Trilobites, either of Upper Silurian or Devonian Age, and “closely resembling Hamilton Group Forms:”—Long. 115° 58´, Lat. 39° 33´, and Long. 115° 36´, Lat. 39° 30´; at these two localities, situated in what are now the Eureka and White Pine Mining Districts, a “group of fossils of decided Devonian type” was found. This group consisted of _Atrypa reticularis_, _A. aspera_, or a closely allied species, a small _Productus_, and three new species of _Spirifer_. This is the most westerly point, on our territory, at which any fossils belonging to formations older than the Carboniferous have, up to the present time, been discovered, so far at least as any published record shows. Between Lon. 115° and 115° 30´ and Lat. 40° 10´ and 39° 20´, is a group or series of hills, trending nearly north and south, and made up “of light yellowish gray, more or less argillaceous and arenaceous subcrystalline limestones and slates.” From these hills fossils were collected which are referred by Mr. Meek to the Upper Carboniferous series. Most of the species were new; among them were three species of _Productus_, two new species of _Spirifer_, and another apparently identical with _S. cameratus_; also, _Athyris subtilita_ and a new species of _Chonetes_ closely allied to _C. Verneuiliana_; these localities are near what is now known as Ruby Valley and Fort Ruby.