OUTLINES OP GEOLOGY. 



59 



metals, but in some countries the grauwacke is rich in them, 

 as, for instance, in Hungary, where it is traversed by veins 

 containing gold. 



143. This group covers a large extent of country in the 

 United States. We have observed it first in the state of 

 New- York, in a narrow ridge, through which the Mohawk 

 makes its way at the Little Falls, and which we have cited 

 as a prolongation of the main chain of the Allegany. A few 

 miles south of this, it meets the western bend of the Catskills, 

 and the formation spreads out to a breadth of 200 miles, be- 

 tween the Pine Orchard and Lake Canandaigua. The south- 

 eastern limit is the Shawangunk mountains, and the blue 

 ridge of Pennsylvania, parallel with which it extends to Geor- 

 gia and Tennessee, in a broad belt, forming the loftiest 

 summits of the Allegany. Of all these ridges it constitutes the 

 eastern face, and dips with more or less rapidity to the N. 

 W., being in some cases almost vertical. On the western 

 slope of many of the ridges, the anthracite coal formation is 

 to be found, resting immediately on the red sand-stone. This 

 anthracite is, therefore, in the lowest position of the coal mea- 

 sures, and is, in some places, said to be evidently beneath 

 the carboniferous limestone ; but those who consider the an- 

 thracite of Pennsylvania to belong to the submedial order, 

 err. 



IV. SUBMEDIAL ORDER. 



Terrains Hemylysiens, Brogniart ; Grauwacke and lower fossiliferous groups , 

 Delabectie ; Transition Formations. 



144. The passage from the former order into the subme- 

 dial, is by no means marked ; and thus the grauwacke which 



