180 



that the Stigmaria are the roots of SigiUaria. From his 

 own study of them, he still had his doubts of this. At 

 the New Brunswick coal-mines he had seen the trunks of 

 SigiUaria imbedded in the rock ; he had even passed 

 beneath them in the coal-mines and seen their roots branch- 

 ing over his head, and they certainly were not Stigmaria. 

 He had noticed, also, in the centre of the markings of 

 Stigmaria, one, and sometimes two, little points. In the 

 Mansfield coal-mines he had seen similar points in the 

 adjacent rock. He was, therefore, inclined to the belief 

 that these markings are leaf-scars. If the Stigmaria are 

 roots, then their rootlets must have been deciduous. 



Dr. Jackson also mentioned the fact, that at the South 

 Joggins, immediately beneath the SigiUaria and coal, 

 there are myriads of fossil marine shells of a mytiliforrn 

 character. 



The President exhibited a cast of a fragment of the left 

 side of the lower jaw of Mastodon longirostris, from Eppel- 

 sheim, and explained the characters of the dentition. 



Mr. Desor said, that some years since a European geo- 

 logist, M. Bouchepon, had attempted to explain the dif- 

 ferent geological formations as due to changes in the axis 

 of the earth. A year and a half since this gentleman had 

 visited the drift deposit at Brooklyn, N. Y., in which 

 Messrs. Desor and Pourtales had found drift shells. The 

 deposit consisted of coarse drift containing scratched peb- 

 bles and shells, and were it not for the presence of shells, 

 would probably have been ascribed to glacial action. 

 Above it are strata of sand and clay. M. Bouchepon 

 referred the strata of this deposit, as delineated by Mr. 

 Desor, to three distinct epochs, in each of which the direc- 

 tion of the earth's axis was diflferent. It would have been 

 impossible, he said, for shells to have occurred in the coarse 

 drift from the neighborhood of the pole. In reference to 

 this subject, Mr. Desor submitted to the Society a letter 

 from Mr. William C. Redfield, of New York, who was 



