being Aptian, and the Patapsco Formation being re- 
stricted to the Albian Stage. 
The Raritan Formation, on the other hand, is Upper 
Cretaceous (Cenomanian-Turonian Stages), according to 
the palynological investigations of Groot, Penny and 
Groot (1961) and Kimyai (1966). The overlying Mago- 
thy Formation is Turonian-Coniacian (Early Senonian) 
in age (Groot, Penny and Groot, 1961 and Stover, 1964). 
It is impossible to sort out the stratigraphic difficulties 
for most of the Atlantic Coastal Plain amber deposits 
from the available literature. It is most important to be 
aware of the age differences of these deposits, however, 
and possible confusion regarding them. The age is par- 
ticularly significant in regard to change in floras and 
seemingly rapid evolution of coniferous elements that 
could have been the amber producers. Although angio- 
sperms were rapidly evolving during this time, none ex- 
cept Liquidambar are known to have beenresin-producing 
plants. 
Washington, D.C. Amber 
A single sample of amber from the Upper Patapsco 
l’ormation was collected by J. Doyle from the corner of 
Branch Ave. and O Street SE, Washington, D.C. The 
amber came from a clay associated with a lignite bed at 
the top of typical Patapsco clays (Lower Cretaceous, 
Albian Stage) which are directly overlain by cross-bedded 
sands thought to be Upper Cretaceous by C.F. Withing- 
ton (Doyle, 1966). Doyle analyzed the plant microfossils 
from these beds and found a typical Upper Patapsco 
assemblage as established by Brenner (1953). Brenner’s 
palynological studies indicate that the gymnosperms of 
the Potomac forest included members of the Podocarpa- 
ceae, Araucariaceae (including Araucariacites australis 
Cook., which is comparable to modern Araucaria and 
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