54 FeatherstonhaugW s Geological Report. 



and which, as has before been observed, reposes upon the 

 conglomerate bed below ; whilst in Connecticut the carbonif- 

 erous rocks alternate with intrusive rocks, and the copper^ 

 according to Mr. Hitchcock, is " found on the margin of the 

 greenstone and coal formation, and the veins always pass^ 

 either laterally or perpendicularly, from one rock into the 

 other." The presence of the copper in both instances is 

 probably owing to the disturbance which in the one instance 

 produced the conglomerate on which the kupferschiefer restSj 

 and in the other to the intrusion of the greenstone beds 

 amongst the beds of the coal formation, laying, frequentl}'' at an 

 angle of 40 degrees with the horizon, beds which originally 

 were deposited on a horizontal line. My own observations 

 of these Connecticut carboniferous beds, which have been 

 made at various intervals, whilst passing too rapidly through 

 the country, have led me to the opinion that they form part of 

 the regular coal measures very partially deposited in this por- 

 tion of the United States. 



The lias is considered to be the lowest formation of the 

 oolitic series of rocks, so called from the calcareous beds of 

 the series being distinguished by the general prevalence of a 

 peculiar structure, their substance being more or less composed 

 of small ovula or concentric egg-form grains of carbonate of 

 lime, resembling the roe of a fish, from which resemblance it 

 w^as usual once amongst mineralogists to denominate oolite 

 rock roestone.* In Great Britain, and on the continent of 

 Europe, this formation has a very general character, sometimes 

 masses of argillaceous marls predominating, and at other times^ 

 especially in the lower portions of the formation, beds of lime- 

 stone, with an occasional oolitic structure. In England this' 

 deposite traverses the whole kingdom, the general direction 

 being east of north, in a somewhat curved line, from near 50° 



* Some beds of the carboniferous limestone are oolitic in the United States, whicb 

 is the case in the same formation in Europe. 



