286 



peculiar rounded form of the dorsal margin ; the umbones not 

 rising so as to interfere with the general outline. The cavity of 

 the beaks is still more shallow ; the sulcation coarser, and the 

 color yellowish rather than green, and on the whole, the shell is 

 more dense and larger. Gould. 



December 1, 1852. 

 Dr. Cabot in the Chair. 



Mr. Stodder mentioned, that a recent cut at East Boston 

 had exposed a curious feature in the drift formation at that 

 place. The drift deposit there consists of a layer of gravel 

 with an undulating surface of uniform thickness, underly- 

 ing a deposit of clay. At the place recently exposed, 

 cracks in the clay are seen from six inches to three or 

 four feet in width, and some of them fifteen feet deep, 

 filled with the drift overlying it. What was the origin of 

 these cracks? 



The Secretary read a letter from Prof. N. Julius Budge, 

 of Bonn, asking an exchange of the Society's Publications 

 for those of the Natural History Society of Prussia and 

 Westphalia. Referred to the Publishing Committee. 



Two pamphlets on the Sugar Cane were presented in 

 the name of Mr. G. H. Gallup. The thanks of the Society 

 were voted for the donation. 



December 15, 1852. 

 The President in the Chair. 



Mr. Hitchcock presented a very perfect specimen of a 

 Crystal of Spodumene, from Norwich. Mass. ; also fossil 



