163 



December 20, 1843. 

 Regular Meeting — Dr. Gould in the Chair. 



Prof. H. D. Rogers, of Philadelphia, gave an interesting 

 account of the Mammoth Cave, in Kentucky. 



He mentioned particularly the incrustations of Sulphate of 

 Lime, which assumes the form of fibrous, columnar crystals, pro- 

 jecting from the walls and ceiling. At first in clusters, and re- 

 sembling in shape rosettes, they afterwards become longer and 

 curved. Prof. Rogers explained the probable manner of their for- 

 mation, which he considered analogous to that of the fibrous col- 

 umns of ice common in clay banks. 



Dr. H. J. Bigelow mentioned similar smaller formations, which 

 he had seen in one of the great pyramids, on the walls of a cham- 

 ber lately opened, specimens of which he had procured on the spot. 

 They exhibit the same fibrous and columnar structure as those of 

 the Kentucky Cave, and probably owe it to the same cause. They 

 are crystals of common salt. 



Dr. Cabot mentioned the occurrence in Yucatan of cavities in 

 the earth called Senotes, resembling closely in their structure the 

 hollow spires or pinnacles in the Mammoth Cave, described by Prof. 

 Rogers. These spires are supposed to be produced by dropping wa- 

 ter wearing away the floor on which it fell, and carving niches and 

 buttresses on the walls. In the Senotes the water is apparently at 

 the same level in all ; from which circumstance, together with the 

 fact that those immediately on the sea coast are brackish, Dr. Cabot 

 was led to suspect an underground communication, by infiltration, 

 with the ocean. 



ADDITIONS TO THE CABINET. 



Specimens of Lichens and Mosses, collected by Dr. Porter, of 

 Plainfield, Conn., and presented by him. The thanks of the Soci- 

 ety were voted to him for the donation. 



ADDITIONS TO THE LIBRARY. 



Collections of the American Statistical Association, Vol. I., Part 

 I. 8vo. pamph. 1843. From the Association. 



Zuccarini, Dr. J. G. — Monographic der Americanischen Oxalis 

 Arten. 4to pamph. From Prof. Gray. 



Annals and Mag. of Nat. History. Nos. 79 and 80. 



System of Nature, by Edward Newman. 8vo. London, 1843 

 From the Author. 



North American Review, for January, 1844. Exchange. 



