341 



to conclude that the oxide of iron has been introduced at and near 

 the surface, by some chemical action, which has at the same time 

 removed the carbonate of lime originally forming the material of 

 the stratum. In looking for an agent adequate to this effect, we 

 naturally refer to tlie sulphate of iron and free sulphuric acid, 

 developed in the adjoining pjq-itous shales, which, brought by in- 

 filtration into contact with the calcareous rock would at the same 

 time dissolve the lime and deposit the oxide of iron in its place. 



Dr. C. T. Jackson observed that he had found, in the oolitic 

 ore from "Wisconsin, that the nucleus of the egg was a grain of 

 sand. In chemical precipitates, a soft solid in a pasty condition 

 is frequently found to pass into a granular state, especially if 

 particles of sand are present, producing imperfect crystalline 

 forms around a nucleus. 



Messrs. Kilby Page and Charles W. Lovett, Jr., were 

 elected Resident Members, and Messrs. Bernard A. 

 Hoopes, of Houghton, Michigan, and H. Davis, of Elgin, 

 Kane Co., Illinois, were elected Corresponding Members. 



DEPARTMENT OF MICROSCOPY. 



Dr. S. Kneeland, Jr., exhibited the spine of an Echino- 

 derm, prepared by Mr. Samuels. 



A collection of marine animals and plants, presented 

 by Mr. N. E. Atwood at the first January meeting, was 

 referred to Dr. Bacon and the Secretary for examination. 



February 17, 1858. 



The President in the Chair. 



Dr. C. T. Jackson stated that he had chemically tested 

 the sugar made from the Chinese Sugar Cane which he 

 exhibited at the last meeting. After boiling it, for a 

 great length of time, with the tartrate of copper and pot- 



