232 W. M. Fontaine—Mesozoie Strata of Virginia. 
drifted ison from some distance, ot but a small num- 
er are well enough preserved to be determined, he texture 
of he clay i is so close that sometimes the entire substance of 
the plant is preserved. 
The summit of the grit is sometimes partly Laminates and — 
contains occasionally a layer of clay, as if a pause in the sedi- 
pantiien had taken place for a short time. On this, or on the 
summit of the grit, there occurs very generally, but not always, 
a very remarkable bed of stones packed in grit like that of the 
mass on which it rests. This latter is more or less eroded and 
trenched. This bed of stones is, I think, the representative of 
the surface pare mentioned above as occurring in the Fred- 
ericksburg Belt. It represents a force which swept over the 
Azoic on the west, as well as over the Mesozoic nee and in the 
Richmond Belt. It seems to have been the clos ing deposit of — 
the Mesozoic series in these border belts for it is followed by 
the Eocene strat 
These stones form a most heterogeneous mass, a true drift 
olga The mass is of varying thickness, usually six to ten 
t. Sometimes, however, it thickens s up to fifteen or more 
u 
Potsdam, usually four to six inches in diameter or under, but 
quite often one and two feet. The smaller stones are well 
which are of Azoic rocks, and include tice found at various 
points to the west as far as the Blue Ridge. It is noteworthy 
large slabs, sometimes showing but little wear. Some vein 
abe from the Azoic, and prageents of the sandstones a the 
ichmond Coal field are seen, but not commonly. Masses of 
the peculiar Shc an ps schists of the Blue Ridge 
far to the west, are not rare. These often attain the dimen- 
sions of three or four feet, and are commonly but little 
abraded. None of these stones or those of the Fredericksburg 
