GEOLOGY: CLARK, BERRY AND GARDNER 
181 
The study of the geography of this region has necessarily a very close 
relationship to the geologic studies of the range, but it may lead also to 
a study of anthropogeography, and to a study of how the present geo- 
graphic conditions are influencing the settlement and commercial de- 
velopment within this district.^ 
^Whitman Cross, U. S. Geol. Survey Geol. Atlas. Silverton folio (No. 120), 1905. 
2 This study is here published with the permission of the Director of the U. S. Geolog- 
ical Survey. 
THE AGE OF THE MIDDLE ATLANTIC COAST UPPER 
CRETACEOUS DEPOSITS 
By W. B. Clark. E. W. Berry, and J. A. Gardner 
GEOLOGICAL LABORATORY. JOHNS HOPKINS UNIVERSITY 
Received by the Academy, February 16. 1916 
Distribution. — The Upper Cretaceous formations of the Middle At- 
lantic Coast area are most extensively developed in New Jersey 
from which state they thin rapidly to the northward through the 
islands off the New England coast, only a few remnants being left in 
southern Massachusetts; while to the south they gradually disappear, 
only the lowermost reaching the Potomac drainage basin. Beyond this 
point they have only been recognized in deep-well borings in Virginia 
although the deposits probably extend continuously beneath the mantle 
of Tertiary formations until they again appear in surface outcrops in the 
South Atlantic area. 
Divisions. — Several formations have been recognized within the area of 
outcrop and have been designated under the names of Raritan, Mago- 
thy, Matawan, Monmouth, Rancocas, and Manasquan. 
Numerous minor subdivisions have been described in New Jersey but 
have been unrecognized elsewhere. All the deposits are of shallow- 
water origin as shown by their contained faunas. The relatively slight 
differences in the faunas of these smaller units are evidently due to the 
var>dng proximity of stream mouths and sediment-bearing currents 
rather than to any differences in depth which may have existed. 
The major divisions, on the other hand, are based on distinct differ- 
ences in the faunas and floras which may be recognized when present 
Qot only in the Middle Atlantic Coast area but throughout the South 
(\tlantic and Gulf regions as well. 
The Raritan and Magothy formations are clearly separable on the 
basis of their contained floras while the Matawan and Monmouth, the 
only marine divisions with equivalents in the South Atlantic and Gulf 
