North Atlantic Pleistocene Problem — Shattiick. 97 
these two parts, the one of which seems to- have affinities with 
the Beacon Hill formation and the other with the Pensauken, 
seem to belong together. * '^ * * 
"In general it (Bridgeton) may be said to contain any sort 
of material which the Beacon Hill formation contains, and some 
which it does not. It is therefore most clearly separated from 
the next older formation by its constitution. But occasionally 
its constitution closely approaches that of the Beacon Hill for- 
mation, and where its topographic relations are at the same 
time indecisive, its differentiation is uncertain. 
"From the Pensauken, on the other hand, it is most clearly 
separated on topographic grounds, especially in the western 
part of the state. Here the Bridgeton beds lie at a level dis- 
tinctly above that of the Pensauken beds, the latter being re- 
stricted to the low area west of the Miocene escarpment. The 
topographic relation of the formations indicates a long interval 
of erosion between their deposition. * * * * 
"Some idea of the former extent of the Bridgeton beds may 
be gained if all existing remnants of it be conceived to be ex- 
tended until they merge into one another, bridging the areas in- 
tervening between the existing remnants. It is believed that 
the formation extended much less far north than that which 
preceded, though the original limits are probably not determin- 
able. 
"It is altogether possible that some of the areas mapped as 
Bridgeton, west of the New Jersey Southern railway, may 
prove to be Beacon Hill instead, and that some of the areas east 
of that line may prove to be Pensauken. The distinction in the 
latter area is based almost whollv on topographic grounds." He 
again mentions a tilting of the Pensauken formation and cor- 
relates the Pensauken with Kansan or Albertan. 
A Pleistocene formation much discussed by professor Salis- 
bury in New Jersey is the Jamesburg. 
His conclusions regarding the Jamesburg formatiiMi mav be 
briefly stated as follows: In the report of 1893, it appears that 
the Jamesburg was deposited on the eroded surface of the Pen- 
sauken. It is aquatic in origin, and the subsidence which made 
possible its deposition amounted to at least 130 feet. The name 
is derived from Jamesl)urg Junction, in Middlesex countv. A 
difficulty is encountered, however, in the absence or obscure- 
