From the Silver Peak District, near lon. 117° 20´, and lat. 38°, an interesting collection of fossils has been brought by Mr. Clayton. The specimens are unfortunately in a very imperfect and fragmentary condition, but they contain the first trilobites which have been brought to our office from any of the Pacific States or Territories. The rock in which they occur is a dark yellowish brown limestone, with intercalated layers of light grey argillaceous shales. Some of them appear to belong to the genus _Dalmania_, and, if so, the formation is probably of Upper Silurian age, although possibly Devonian. The careful examination of the corals which have been obtained in this district by Mr. Clayton, and also by Mr. Blatchley, will probably throw some additional light on the geological position of these rocks. [26] On Professor Hall’s Map “illustrating the general geological features of the country west of the Mississippi River,” which accompanied Emory’s Mexican Boundary Report, and was published in 1857, all of a broad central strip running along the parallel of 40° through the center of Nevada, is colored as “lava and other igneous rocks,” while the western portion of the State has several broad belts of “Upper Carboniferous Limestone,” running north and south across it from Walker’s Lake to Goose Lake. So far as I know, no Carboniferous fossils have yet been found in that part of Nevada. [27] See Jahrbuch der K. K. Geologischen Reichsanstalt, 1865, page 233 of the Proceedings. REGULAR MEETING, JUNE 4TH, 1866. President in the chair. Eleven members were present. The following named persons were elected Resident Members: C. R. King, Frederick Gutzkow, Theodore Blake, W. A. Goodyear, Charles Bonner, C. W. Lightner, Hugo Hochholzer, James T. Gardner. Donations to the Cabinet: Copper Ore, from Yarrow mine, near Lexington, Santa Clara county, and Molybdenite, from Coloma, El Dorado county, from Mr. Hanks. Land, river, and marine shells collected in Central and South America by the late Thomas Bridges; presented by Mrs. Bridges. Two birds from Mr. Lorquin. A collection of Australian plants, from Dr. Ferdinand Müller. Lichens from Plover Bay, collected and presented by Mr. Dall. Donations to the Library: Verhandlungen der kaiserlich en Leopoldino-Carolinischen deutschen Akademie der Naturforscher, Band XXXII, 1ste Abtheilung; 4to Dresden, 1865. Amtlicher Bericht über die 39te Versammlung Deutscher Naturforscher und Aerzte in Giessen im September, 1864; 4to, Giessen, 1865. Jahrbuch der k. k. geolgischen Reichsanstalt; 1865, Band XV. No. 4, roy. 8vo. Wien. Nachrichten von der k. Gesellschaft und der Georg-Augusts-Universität, aus dem Jahre 1865; 12mo. Göttingen. The above were presented by the different Societies named, and forwarded through the Smithsonian Institution.