6 THE OLDER MESOZOIC FLORA OF VIRGINIA. 



different in character. Nevertheless, certain broad features can be made 

 out, and these only will be given here. 



The more westerly areas, such as the Pittsylvania, Buckingham, and 

 Palisade, contain no coal and possess a large proportion of red beds. The 

 more easterly areas, the Cumberland and Richmond, contain coal and 

 show little or no red beds. The amount of these red beds diminishes as 

 we leave the vicinity of the Blue Ridge. 



The Cumberland Area contains much more of them than the Rich- 

 mond Area. In both of these the red strata, when found, occupy the 

 lowest horizon. The strata of all the areas may be divided into three 

 groups, and this division is most marked in the two coal-bearing areas. 

 The coal in these occurs in the middle group, and is accompanied by a 

 large proportion of black shales. The lowest beds of the two coal-bearing 

 areas are sandstones and shales, of a predominant gray color, but with some 

 red strata, which, however, in the Richmond Area are unimportant. The 

 upper group, or series, is without workable coal in these two areas. It 

 contains, however, in places, much lignite, which sometimes approaches jet 

 in character. Some silicified wood is found on this horizon. In general, the 

 upper strata of the Cumberland and Richmond Areas are loose granitic 

 sandstones or sandy shales. The granitic sandstones often contain the 

 ingredients of granite partly decomposed and unsorted. In some parts 

 deposits of bowlders occur among the upper beds. The stones are some- 

 times many feet in diameter, and seem to have been transported from a 

 distance. These bowlder deposits occur in all the areas, and on their 

 western margins. The more western areas, the Buckingham, Pittsylvania, 

 and Palisade regions, show also the threefold grouping of the strata, but in 

 a less marked manner. Where plants and traces of coal occur in them 

 they are found in the middle member. This member contains a compara- 

 tively small amount of red beds. The beds are here often gray, or green- 

 ish-gray. The lower group of these areas is usually characterized by the 

 large amount of red strata present and the absence of traces of vegetable 

 matter except silicified wood. The upper group or member varies in 

 character with the locality, but it does not here (as in the coal-bearing 



