Featherstonhaugh's Geological Report. 58 



any rocks in the United States which deserve to be examined 

 with the most precise accuracy, with a view to institute a com- 

 parison with the members of this group, I should point to those 

 which are included in Mr. Hitchcock's paper* on the geology 

 of the Connecticut, where, amidst red argillaceous schistose 

 sandstones, in the valley of the Connecticut, fossil fish are 

 found in a bed of bituminous shale of a mean thickness of about 

 ten feet. Mr. Hitchcock states in that paper that Mr. Brog- 

 niart was of opinion the Connecticut formation had the strong, 

 est resemblance to that of the bituminous marl slates of the 

 copper mines in the country of Mansfeldt and Hesse, and that 

 he did not consider the occurrence of thin beds or veins of 

 coal as opposed to his opinion, which of course was founded 

 upon description and upon specimens. These seams of coal 

 are thin, not exceeding one inch, yet sufficiently numerous to 

 have induced Mr. Hitchcock, in his minute and admirable 

 paper for the period in which it was drawn up, (1822,) to 

 name it the coal formation, a term which invites a great deal 

 of investigation, on account of the great value of the results 

 connected with it. I would remark here, that the occurrence 

 of seams of bituminous coal by no means identifies the rocks 

 in which they are found with the regular coal measures, since, 

 without speaking of other portions of the geological column, 

 it is stated by Professor Puschf that seams of coal from three 

 to twenty-five inches thick are found in Poland between the 

 muschelkalk and the oolitic series, in the very group now un- 

 der consideration a circumstance which strengthens the anal- 

 ogy between this group in Europe and the coal formation of 

 Connecticut. To this may be added the important fact of the 

 presence of copper in both formations, which, although exist- 

 ing under different conditions in each of them, may have been 

 produced in each by the same cause. In Germany the copper 

 is obtained from the stratum of slate in which it is distributed, 



* Silliman's Journal, vol. 6, p. 73. t Journal de Grologie. 



