Professor Whitney made some remarks on the geology of the State of Nevada, of which the following is an abstract. Having recently received a small but very interesting collection of fossils, made in Nevada by Mr. J. E. Clayton, the examination of which has added considerably to our scanty stock of information in regard to the geology of an extensive region comprised between the meridians of 115° and 120°, and the parallels of 38° and 41°, I take this occasion to set forth, in a very concise manner, the information which I have collected, up to the present time, in regard to the age of the sedimentary formations of the regions in question. The State of Nevada occupies a portion of the continent which, during the last few years, has received a large share of attention from the public and excited the greatest interest among scientific men; but where, up to the present time, detailed geological work has been impossible, owing to the absence of any geographical map of the State approaching even to accuracy. The U. S. Pacific Railroad Surveys furnished no geological information whatever in regard to the territory embraced within the present area of the State of Nevada. The route from Salt Lake to Humboldt River, at Lassen’s Meadows, was hastily explored by Captain Beckwith, in May, 1854, and he was accompanied by Mr. Schiel as Geologist; but no information of any value is given in regard to the geological structure of the region traversed by the party, nor were any fossils discovered, although portions of the rocks along their route have since been proved to be prolific in organic remains. On all the geological maps of the whole territory of the United States which have been published up to the present time, the region west of the Rocky Mountains has been so misrepresented that it is quite impossible to trace any approximation, or first hinting, at either the age or the outline of the principal formations. On these maps the region lying between the Salt Lake and the Sierra Nevada is usually left uncolored, or vaguely designated as “metamorphic” with patches of “volcanic” and “desert quaternary” scattered through it at random.[26]