North Atlantic Pleistocene Problem — Shattuck. 95 
In the report for 1894 professor Salisbury points out that a 
submerged trough formerly existed in central New Jersey ex- 
tending from Raritan bay to Delaware bay, allowing a com- 
munication between these two bodies of water and separating 
southeastern New Jersey from the mainland as an island. In 
this trough were deposited the Pensauken and Jamesburg for- 
mations and the Trenton gravel. Various elevations of the 
Pensauken are also mentioned in this report. The most noted 
differences in elevations are the following: at Fish House, the 
elevation of the Pensauken is stated as 15 feet where it lies im- 
mediately under the Fish House clays, the latter being regard- 
ed here as post- Pensauken. Nine miles southeast of Fish 
House, the base of the Pensauken is at an altitude of 150 feet, 
thus making a rise of 15 feet per mile. Professor Salisbury 
also reaffirmed the deformation of the Pensauken surface since 
its deposition. The age of the Pensauken is ascribed to thp 
Lafayette in the following terms : "There can no longer be any 
doubt that the Pensauken is the equivalent of the Lafayette for- 
mation of the south. This conclusion was reached tentatively 
more than a year. since." 
In the report for 1895 professor Salisbury points out that 
the base of the Pens&uken formation dips to the southeast in 
harmony with the Miocene and also inclines toward Delaware 
river. He also somewhat doubtfully refers the Fish House 
clays to the Pensauken. The Pensauken formation in the 
trough extending from Raritan bay to the Delaware river, as 
well as the Pensauken formation southward along the south- 
eastern bank of the Delaware are here mapped. On this map a 
large body of gravel found south of a line extending from Phil- 
adelphia to Atlantic City is represenfed as Pensauken, and so 
stated in the report. A number of sections are given to make 
clear his conception, in which the profile distinctly shows a 
marked diiTerence in the elevation of the Pensauken from its 
lowest position near the Delaware river tO' its highest altitude 
in the vicinty of Glassboro and neighboring points. To ac- 
count for this topographic difference a number of hypotheses 
are suggested, such as monoclinal folding, faulting, or possibly a 
bifold division of the Pensauken formation. In this connection he 
says : "From sections 2. 3 and 5 it would appear that the Pen- 
sauken might be a bifold formation." Put he still regarded 
