ACADEMY OF SCIENCES. 149 



Dr. Hcuston made a motion, which ^-as carried, that Prof. Es- 

 mark be allowed the use of the rooms of the Academy, and that the 

 specimens of crustaceans and fishes be put in his charge for the pur- 

 pose of classification. 



Regular Meeting, December 19tii, 1870. 

 President in the Chair. 



Twenty members present. 



Donations to the Museum : Bones of a mastodon, from Inyo 

 County, by Dr. Blake, who remarked that he hoped to obtain the 

 head also. Larv» of a Cicada, from Mazatlan, Mex., with fun^i-oid 

 groAvths from their heads, of the genus Spheria, (like S. Robertsii, 

 often exhibited on a Chinese caterpillar) from Mrs. A. J. Grayson, 

 through Mr. Carlton. A West Indian sponge, from Dr. Bourne. 

 Fresh water mollusca, also a Spirifer from the Wasatch Mountains 

 from Dr. R. F. Reid, found in Utah, etc., through Dr. Trask. 



Donations to the Library : 



Reports on Provinces of China, Baron F. Von Ricbthofen.Slianghai, 1870, 

 1 vol., 4to. Coa! Fields of the North Pacific Coast, R. Brown, Edniburg, 

 (Geo). Snc.) 18(19, pam., 8vo. Genus Pompliolyx and its allies with revision 

 of the Limna'idie, W. H. Dail, (An. N. Y. Lyceum) 1870, pam., 8vo. Mililary 

 maps of Virginia, Engineer Dept., Washiniiton, 1870, folio. Journal of Gas 

 Lighting, etc., London, Nov. 22d, 1870, folio ; E. Doll, Vienna, 1870, pam., 

 8vo.; Overland Monthly for January. 1871, I vol., 8vo.; American Journal of 

 Microscopy, No. 1, Chicago, Nov., 1870, 4to, from the Publishers. 



Dr. Le Plongeon continued the reading of his essay on Earth- 

 quakes. 



Prof. Davidson stated that in studying the bars and entrances to 

 all the rivers and bays opening directly into the Pacific along our 

 coast, he had discovered the general law that the channels all tended 

 to the northward, directly in the face of the northwest wind and 

 northwest swell rolling steadily all summer. He attributed this to 

 the eddies running within the great northwest current, and, of 

 course, contrary to it, usually with a velocity of two miles per hour 

 and width of about three miles. The sand was rolled northward 



