OLDER POTOMAC OF VIRGINIA AND MARYLAND. 573 



is confined to the Rappahannock horizon, its presence denotes an 

 Arundel or Rappahannock age for the beds containing it. This appears 

 to have been somewhat smaller than the one figured in Monograph XV. 

 It is given in PL CXIX, Fig. 8. It was collected b}^ Mr. Bibbins for 

 the Mar^dand Geological Survey in August, 1899, and bears the number 

 5312 of that survey. 



FOSSIL PLAMS FROM LOCUST OK POPLAU POINT. 



[PI. LXXX, No. 10.] 



Locust or Poplar Point has yielded to the collections five or six 

 rock fragments with plant matter. The rock material is an ash-gray, 

 rather arenaceous shale, stated on the labels to be Patapsco in age. 

 This cla3^ has a good msury bits of carbonized vegetable matter which 

 are not determinable. Two specimens, however, are small cones that 

 are most probably cones of Athrotaxopsis ezpansa, but which can not 

 be determined positively as such. The evidence from these is not 

 sufficient to locate the horizon of the plants. This Athrotaxopsis is, 

 in the Virginia localities, most characteristic of the Rappahannock 

 horizon. 



The material containing these impressions was collected by Mr. 

 Bibbins in July, 1897, for the Maryland Geological Survey. It is all 

 under one label marked M. G. S., No. 5316. A single specimen col- 

 lected in August, 1899, and marked M. G. S., No. 5315, shows nothing 

 determinable. 



FOSSIL PLANTS FROM GIUYS HILL. 



[PL LXXX, No. 6.] 



A few plants are credited on the labels to Grays Hill, Cecil County, 

 formation Patapsco, collected l:)y Mr. Bibbins for the Maryland Geo- 

 logical Survey in August, 1899. The rock material is much like that 

 from Vinegar Hill. The determinable fossils are 1 specimen of Podo- 

 zamites distantinervis Font, and 2 of Sphenolepidium Sternbergianum 

 densifolium Font. They probably belong to the former. The plants 

 do not suffice positively to determine whether the Grays Hill strata 

 correspond to the Rappahannock or to the Aquia Creek member of 

 the Virginia Potomac. 



