118 [November, 1841. 



donations to library. 



Proceedings of the Botanical Society of London, for 1839. 

 8vo. From the Society. 



American Journal of Science and Arts. Vol. 41. No. 2. 

 Oct. 1841. From the Editors. 



Written Communications. A letter was read from Dr. 

 Frederick Tamnau, Jr., of Berlin, acknowledging the receipt 

 of his diploma of membership in this Society, and soliciting an 

 exchange of the minerals and fossils of Germany for those of 

 America. 



Professor Johnson made some remarks on the samples of 

 Anthracite from Rhode Island, this evening presented, and 



stated 



That the formation in which they occur, reposes on a coarse con- 

 glomerate, which rests immediately on granite or hornblende rocks 

 of the primitive series. The near proximity of primitive rocks 

 appears to have exercised an important influence, not only on the 

 position, but on the present character of the anthracite of this for- 

 mation ; for while it has thrown the beds into a highly inclined posi- 

 tion, it has expelled the last vestiges of volatile matter, decomposed 

 the sulphuret of iron, and changed the colour of the coal in some of 

 the beds to a nearly steel blue. The vegetable impressions are in 

 these cases to a great extent obliterated, and the traces of them 

 only appear at the surfaces of deposition. In other beds, the im- 

 pressions are more perfect, and their genera and species are more 

 readily made out. 



An idea has been formerly current, that the coal formation of 

 Rhode Island and Massachusetts is of more ancient date than those 

 of Pennsylvania ; but the identity of fossil remains occurring in 

 both, seems to determine the geological period of both to be the 

 same. And in this respect we have analogies sufficiently numerous 

 in our own country, to induce us to believe that all the coal forma- 

 tions are essentially contemporaneous, and that whether they rest on 



