VESPERTIlsrE GROUP. PP. 3 



of succession, and the charactei- of the strata, to form an 

 intelligent idea of the occurrence of the plants, and to gain 

 some knowledge of the changes shown, in ascending from 

 lower to higher horizons, in the Carboniferous strata of 

 West Virginia. 



The Vespertine Group. 



At the base of the Carboniferous strata in West Virginia, 

 we find the Vespertine G-roup, which contains the oldest 

 land plants yet found in this State. The group being a 

 shore formation, is quite variable in thickness, thinning as 

 we proceed from the east (which was the ancient shore) 

 to the west. It thickens in a remarkable manner to the 

 north and south of the northeastern corner of the State. 

 Along the eastern border of this State, it ranges in thick- 

 ness from about 200 feet, to over 1000 feet. The lower 

 limit is given on the authority of Prof. Wm. B. Rogers, 

 who determined this thickness on the Potomac River, in 

 Hampshire county. 



Owing to the absence of fossils, and the great variability 

 of the strata for some distance above the highest strata of 

 the Chemung containing fossils, there is some difficulty 

 about fixing the base of the Vespertine, unless, as seems 

 natural, we accept as a base the first stratum which, by its 

 persistence and well marked physical character denotes a 

 decided and widely prevailing change in the conditions of 

 deposition. Such a stratum we find in a peculiar conglom- 

 erate which everywhere makes one of the lower members 

 of the Vesj)ertine Group, and which is the very lowest 

 which can be identified at widely separated points. 



This rock is a highly siliceous white sandstone, and is 

 almost always a pronounced conglomerate. It usually has 

 large pebbles which have the peculiarity of being flat, in- 

 stead of possessing an ovoid or elliptical form, as is usually 

 the case with the pebbles of conglomerates. These flat 

 pebbles characterize this rock at widely separated points, 

 such as Montgomery Co. Va. and Cheat River in Monon- 

 galia Co. W. Va. 



Between this cony-lomerate and lower beds which are cer- 



'n' 



