Il and Kreischerville, on the one hand, and Alaska III 
and Washington, D.C., on the other, in the intensity and 
resolution of the carbonyl band. The 11.3 » (855 em-!) 
band is most pronounced in Alaska If and Washington, 
D.C. (H 173 on Plate XV). 
Spectra of resin from various living members of the 
‘Taxodiaceae and Pinaceae are being run presently to see 
if correlation can be established with these Alaskan types. 
The Taxodiaceae are of particular interest, since associ- 
ated plant remains with the Alaskan amber point to this 
possible origin. As yet, however, relation of this amber 
to either members of the Pinaceae or T'axodiaceae is not 
evident, but further investigation of the modern resins 
is necessary. 
Atlantic Coastal Plain Amber 
Amber for spectral analysis has been obtained from 
twelve localities along the Atlantic Coastal Plain from 
Massachusetts to South Carolina (Fig. 1). In most cases, 
the amber was reported to occur in Potomac, Raritan 
or Magothy beds. Controversy has existed regarding the 
age of these stratigraphic units (Spangler and Peterson, 
1950; Dorf, 1952; Steeves, 1959). Recent palynological 
studies, however, have essentially confirmed age assign- 
ments previously based on plant megafossils (Berry, 
1909, 1910, 191lla,b,c, 1914, 1916 et al.; Dorf, 1952). 
The Potomac Group is the basal unit of the Atlantic 
Coastal Plain Cretaceous sequence in Maryland, Dela- 
ware and Virginia. It typically underlies the Raritan 
and Magothy Formations in Maryland and Delaware 
but is absent to the northin New York, New Jersey and 
Massachusetts, where the Raritan is the oldest Cretaceous 
unit. The Potomac Group appears to be entirely Lower 
Cretaceous in age (Brenner, 1968), with the Patuxent 
Formation being Barremian, the Arundel Formation 
[ 75 ] 
