358 LTTE OGLTAN ALL OLIN GILROVEO GN 
Report on Surface Geology. By Rouiin D. Savissury, in Annual 
Report of the State Geologist of New Jersey, for 1893, pp. 
35-328. Pl. 1-6, and three large-scale, folded maps. 
This is the third report of progress which has appeared on the 
detailed studies of the surface geology and topography of New Jersey 
now being made by the Geological Survey of that state. The results 
recorded are the outcome of the field work in 1893, conducted by Pro- 
fessor Salisbury, who was assisted for longer or shorter periods by 
Messrs. H. B. Kiimmel, C. E. Peet, A. R. Whitson, and G. N. Knapp. 
The area examined is practically the northern third of the state. 
Observations were confined to the records of glaciers, and to certain 
gravel deposits more or less closely associated with ice invasions. The 
order of treatment is chronological, beginning with the oldest records 
that have been thought to belong to Pleistocene time. 
The Yellow Gravel.—The occurrence of detached areas of gravel and 
sand, from the latitude of Staten Island southward has been known for 
several years, and usually designated as ‘‘ Yellow Gravel,” and referred 
in part to the Columbia and Lafayette formations. When traced south- 
ward, the areas occupied by this deposit became larger, and are believed 
to coalesce finally so as to form a continuous sheet, having a wide 
geographical range. Along its northern margin this deposit attains a 
maximum elevation of nearly 4oo feet above the sea, and declines 
gently southward. It has usually been considered a single terrane, but 
the report before us proves that it includes at least four distinct deposits 
differing widely in age. Three of these divisions have been given 
local names as follows, beginning with the oldest: Beacon Hill, 
Pensauken and Jamesburg. The fourth and youngest phase is not 
named. 
While the more obtrusive lithological characteristics of these four 
terranes are similar and in a general way are expressed by term Yellow 
Gravel, yet careful study has shown that they differ widely in composi- 
tion and that the pebbles they contain were derived from widely 
separated sources. The Beacon Hill gravel is characterized by the 
presence of yellowish quartz, chert, flint and sandstone pebbles, and 
by the entire absence of shale and granitic material. The constituent 
pebbles range up to three inches in diameter, and cobbles and moder- 
ately worn slab-shaped fragments, two feet in diameter are occasionally 
found. In the Pensauken which was derived largely from the Beacon 
Hill, there is an addition of material from widely separated sources to 
