48 Fealherstonhaugli^s Geological Report. 



itself in the Ohio ; resembling in a degree the calcareous 

 masses in England and Wales which have given rise to the 

 name of mountain limestone. The conglomerates likewise, 

 which in some parts of the country alternate with the lower 

 beds of the carboniferous limestone, in others are entirely 

 detached from it, and form the upper bed of the old red sand- 

 stone, as is more frequently the case in Europe. These local 

 differences in the condition of proximate beds, whilst they 

 show an irregularity of action in particular localities, prove 

 that the same cause to which they owe their origin operated 

 to produce these analogous deposites in both hemispheres. 

 Extreme as the difference is between the state and extent of 

 the carboniferous limestone in various parts of the United 

 States, it is equally remarkable in Europe, especially in Great 

 Britain. There, no district where this formation prevails, 

 can scarcely be said to furnish a perfect mineral type to com- 

 pare with that of any other part of the country, so much are 

 the calcareous deposites varied by alternations of shale, the 

 thinning out of beds, and other incidents. An adequate knowl- 

 edge of the organic remains belonging to this formation will 

 however be a suflicient guide to the student to identify the 

 deposite. 



The great purity of most of the beds of the carboniferous 

 limestone furnishes strong evidence that they have been de- 

 posited from mineral waters holding carbonate of lime in 

 chemical solution, as we find them doing in our times. It is 

 true some of the beds are intermixed with argillaceous matter, 

 and hence become less fitted for economical purposes ; but this 

 circumstance disposes to the belief that these strata had their 

 origin from below, rather than from the destruction of pre- 

 existent continents, an opinion which some have entertained, 

 since, in this latter case, the heterogeneous admixture must 

 have been more general. A great number of the beds are loaded 

 with nodules and layers of chert, resembling, in a remarkable 

 degree, in their connexion with the limestone, the manner in 



