220 Part III. Chapter 3. 
‚developed subsequent to the post-Pensauken uplift of the New Jersey geologists') 
which occurred prior to the glaciation of the northern hemisphere. During the 
Pensauken submergence of the New Jersey geologists') which occurred prior to 
the glaciation of the northern hemisphere, New Jersey was depressed to such 
an extent as to drown the Delaware River at its lower end, allowing the sea 
to pass up its valley and over the peneplain which had been developed during 
the previous cycle of erosion, so that a broad sound was formed which con- 
nected Raritan Bay with Delaware Bay, forming an island covered perhaps 
with pine barren vegetation. The mouth of the Delaware River during the 
post-Pensauken uplift was transferred to Delaware Bay followed by a cycle of 
erosion which lasted until the ice of the last glacial epoch invaded the northern 
portion of the state. It was during the post-Pensauken uplift that the flora of 
the lower Delaware Valley and the coastal strip was probably developed, so 
that the New Jersey pine barrens became* surrounded by a fringe of vegetation 
developed along similar Jines in the coastal strip and along the east and west 
banks of the Delaware River. 
Pine barren Flora. Another illustration of the historic factors instrumental 
in plant distribution and one connected with the development of the pine barren 
flora in general is afforded by the peculiar flora of the Kittatinny of 
Shawangunk Mountains of northwestern New Jersey. This mountain chain 
forms a wall of almost constant altitude, averaging over 1200 feet in height, 
along the eastern side of the Delaware River from Port Jervis to the Delaware 
Water Gap. Its summit and western slopes are composed of a coarse, Of 
fine, very hard silicious conglomerate, or sandstone, with little soil but that 
derived from the limited disintegration of these rocks and it is, therefore, 
highly silicious. While the mountain sides were extensively glaciated, there 15 
very little glacial drift on the ridge. On these mountains exist a number of 
plants which occur also in sandy soil along the Atlantic coast. Among the 
noteworthy species, according to N. L. BRITTON, are Juncus Greenü, Solidago 
puberula, Orontium aquaticum, Tephrosia (Cracca) virginiana, Lespedesa hirta, 
Lupinus perennis, Quercus ilicifolia (= O. nana), Corema Conradii. At Culver’s 
Gap were found by BRITTON, Polygala polygama, Gerardia pedicularia, Lechea 
racemulosa, all abundant along the coast and Prunus pumila. Another pecu 
liarity is the substitution of Pinus rigida on the mountains for Pinus strobus 
of the surrounding country. 
The reason for the somewhat remarkable similarity of the pine barren and 
summit mountain floras is usually attributed to the similarity of the soil on 
the mountains to that of the plains bordering the coast. It is probably true 
that the plants occupy these areas, because they have adapted themselves t0 
growing in soils of silicious sands, but to say that the soil is the prime factor 
in their distribution is putting the case too strongly. It appears that the flora 
ne 
1) Cf. SALISBURY, J. D.: The physical Geography of New Jersey, Geological Survey of New 
Jersey, IV. 
