156 W. M. Fontaine—- Mesozoic Strata of Virginia. 
erosion and other causes have caused it to pass over a shor 
distance on the newer beds, but it soon disappears within the 
areas occupied by such beds. In Virginia we have no means 
of determining whether the drift follows the surface of the 
upper series as it passes eastward under the Tertiary, but in 
Maryland it evidently passes eastward under the Cretaceous. 
Thus the wells bored to the southeast of Baltimore penetrate it 
on entering the clays and sands of the upper series. I have 
carefully examined the Maryland Reports for information on this 
head, and find that they give evidence that this bowlder deposit 
passes as far to the southeast as its horizon has been reached. 
Fossil Plants.—These can be only briefly noticed. I bave 
found a large number of well preserved plants at Fredericks- 
burg in the lower series. They occur in a gray clay or shale, 
which rests on a bed of cobble-stones. I owe the discovery of 
the deposit to Professor P. R. Uhler, President of the Maryland 
Academy of Sciences. The material which imbeds the plants 
is not laminated, and the plants all seem to have been drifted. 
Considering their mode of occurrence, the smal] amount of change 
exhibited by some of them is wonderful. As the deposit is very 
local, it has hitherto escaped attention almost entirely. Many of 
the plants retain their entire structure, and are only colored 
have some which seem still to possess their chlorophyll! 
They have a decidedly green color. They are principally Con- 
ifers, Cycads and Ferns. No species of the Richmond Coal field 
- are found here, but a few show affinities with Rbaetic plants. 
of New Jersey and of the west, we should expect to find, at 
least, their ancestors in the Jurassic flora. 
This flora, as a whole, is decidedly younger than that of the 
Richmond Coal field. Its rather complex type will require 4 
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