ACADEMY OF SCIENCES. 51 



Regular Meeting, May 1st, 1876. 

 President in the Chair. 



Thirty-two members present. 



Edward P. Morse, Walter Damenburg and Rudolph Thor- 

 maim were proposed for membership. 



Donations to the Museum: Rock Salt from T. J. Butler; mar- 

 molite containing gold, from Gov. S. Purely; silver ore, (South 

 Barcelona mine) from Louis Blanding; silver ore, (Leopard 

 mine) from Mr. Marshall, through Henry Edwards; ten speci- 

 mens Amianthus; specimens of common salt;forty-five specimens 

 of copper ore from Inyo and Placer Counties, argentiferous gal- 

 ena, flint nodule, from C. D. Gibbes; specimens roofing slate 

 and purple slate, from Gen. John Hewston, Jr.; rock salt, from 

 H. Robinson; six specimens rich gold quartz and amianthus, from 

 Dr. J. M. Hill; Mus decumanus, from Wm. Barber; beetles from 

 India, from Prof,. Davidson; Tubicola longijjes, from W. N. Lock- 

 ington; Lockingtonia jluvialis, and Alloniscus masculosus, from 

 W. G. W. Harford; four specimens of birds, from W. G. Blunt. 



The President spoke of the tarantula, and presented and 

 quoted P. Martin Duncan to correct a misapprehension concern- 

 ing the insect. 



Dr. Blake presented a specimen of infusorial .earth obtained 

 from the hills about a quarter of a mile south of the N. E. 

 end of Lake Merced. The deposit was known as the "chalk 

 mine," and a considerable quantity of it had been sent to the 

 Eastern States, as he understood, for the purpose of polishing 

 glass. The deposit has been opened on the side of the ravine. 

 So far as exposed, it appears to form a continuous stratum which 

 has been cut into so as to expose a section of about four feet in 

 thickness, although it probably is much thicker, as the whole 

 hill for some distance seems to be formed of it. It was # traced, 

 cropping out at intervals, a distance of 300 yards to the west 

 of where it had been opened, beyond this to the west the sur- 

 face of the hill was covered by shifted sand. The bed has a dip 

 of about 20°, a little to the E. of S., and appears to be undis- 

 turbed. The highest part of the outcroppings is at an elevation 



