These inclusive with the continental series foot up eighteen days on which shocks occurred in excess of this coast during the same period of time, and thus shows a margin of greater frequency of little more than thirty per cent. ERRATUM. Page 131, line 16 from bottom, for “an oven” read “or even.” REGULAR MEETING, MAY 2D, 1864. Dr. Trask in the Chair. Eleven members present. Donations to the Cabinet: Specimens of dried plants, the types of species lately described in these proceedings by Prof. Gray. Mr. Brewer presented for Mr. Gabb the following paper: On Cretaceous Fossils from Sahuaripa Valley, State of Sonora, Mexico, discovered by August Rémond BY W. M. GABB. Mr. Rémond announced in a letter to me, the discovery of fossiliferous rocks about a league and a half east of Arivechi, Sahuaripa Valley, Sonora, Mexico. The fossils occur in a clay slate, and are in a fine state of preservation. He says: “The shales rest on sandstones, barren of fossils; feldspathic porphyries protrude through them, but no alteration of the beds were observed at the points of contact. Even the lamination of the fossiliferous strata has not been disturbed, and shells are found but a few millimetres from the porphyry.” He adds that the fossil bearing strata may attain a thickness of four or five hundred feet. The shales are overlaid by thick strata of compact blueish limestone. The strata dip to the south-east with an inclination of from thirty to fifty degrees, and form the first range of foot-bills of the Sierra Madre. I have identified the following species on a hasty examination, proving conclusively the cretaceous age of the formation. It is an interesting fact, that the fossils indicate a closer relationship to the eastern deposits than to those of California. Turritella seriatim-granulata Roem. Cardium Tippanum? Con. Chemnitzia (?) gloriosa Roem. Trigonia Evansii? Meek. Neithea quadricostata Sow. Exogyra Texana Roem. Turbinolia Texana Con. REGULAR MEETING, MAY 16TH, 1864. President in the Chair. Fourteen members present. Rev. Mr. Neri, of Santa Clara, was elected a corresponding member. Donations to the Cabinet: Volcanic cement, from Sierra County, containing fossil wood; also a magnesian mineral, from a cavity in a quartz vein near Nebraska, Sierra County. Mr. Clayton stated that when found it was gelatinous, semi-transparent, and mixed with loose quartz crystals; but on drying it shrank greatly in bulk and became fibrous, like fine Asbestos. The miners say that it is not uncommon in that locality. Seeds of a large Melon Cactus, from the Colorado deserts; also seeds of a fine nutritious “bunch grass,” from the dry foot hills near Fresno river, by Mr. J. E. Clayton.