Makyland Geological Survey 63 



of faulting suggested, although no definite evidence on that point exists. 

 It is evident, however, that a warping of the beds occurs whether with 

 or without dislocation of the strata. The main body of the deposits may 

 well have been subjected to deformation in the many differential move- 

 ments which are known to have taken place in the Coastal Plain in post- 

 Patuxent time. Furthermore, some of the marked changes in dip in 

 the later formations, as notably in the Magothy formation along the line 

 of the Chesapeake and Delaware Canal, suggest the possibility of actual 

 folding of the underlying formations. 



Organic Eemains. — Although the Patuxent deposits are in general 

 unfossiliferous because of their coarse character, nevertheless a consider- 

 able flora, has been collected from clay balls and lenses and the more 

 argillaceous sands, especially from beds of this age in the Eappahannock 

 and James river valleys in Virginia. 



This flora includes a large element made up of survivors from the 

 older Mesozoic, and is rich in species and individuals referred to the 

 fern genera Cladophlehis and Onychiopsis. Other genera of ferns, such 

 as Acrostichopteris, Schizceopsis, Scleropteris, Tceniopteris, liuffordia, 

 etc., are less common. A variety of cycad remains testifies to the 

 abundance of this type of plant, represented for the most part in the 

 Maryland area by the silicified trunks of Cycadeoidea, of which several 

 different species are known. Cycad fronds, less common in Maryland, 

 are abundant in the more argillaceous deposits of this age in Virginia, 

 and include a variety of genera such as Nilsonia, Podozamites, Zamites, 

 WilHamsonia, Ctenopteris, Ctenopsis, Ctenis, etc. Perhaps the most 

 striking of these remains are the large forms of Nilsonia and the splendid 

 fronds of Dioonites. 



Among the gymnosperms are species of 8plienolepsis, Baiera, Brachy- 



phyllum, Frenelopsis, Nageiopsis, Arthrotaxopsis, Sequoia, and Cephalo- 



taxopsis. These are for the most part genera that range from the late 



Triassic to the Upper Cretaceous. They are abundant in the Patuxent 



and represent families which in the modern flora are largely natives of 



other continents. 

 5 



