Condition of the Earth’s Interior —Mountain- Making. 9 
aes small and of varying extent during the Silurian and 
evonian ; for Devonian fossils show that the sea-border south of 
New York had some way an open connection with the Atlantic 
ocean ; but there is no evidence in the Appalachian rocks of the 
Carboniferous era to prove that off New Jersey it was not, at 
that time, almost or quite a complete barrier; the marine fossils 
in the more eastern of the Pennsylvania Coal-measures are rare, 
and those in the western Pennsylvania beds would have been 
from the waters of the mediterranean sea over the Mississippi 
basin, which reached northward from Alabama, and, east of the 
Cincinnati uplift, bathed all the western ae of the Appala- 
geanticlinal; for it was still above the ocean 
following era—the Triassico-Jurassic. The absence of all re- 
mains of distinctively marine fossils from these rocks, and from 
any rocks of the Triassic or Jurassic eras in view over the 
Atlantic border, demonstrate (as I have long held) that an 
emerged area then existed outside of the present coast line. 
Moreover, inasmuch as these Triassico-Jurassic areas (situated 
on the Atlantic slope parallel with the Appalachians) were sub- 
siding while their rocks were in progress, the sea-border anti- 
clinorium should, at the time, have taken another turn upward, 
a8 a counterpart to this subsidence. 
With the close of the Triassico-Jurassic era, if not before, 
the great anticlinorian barrier began actually to disappear; and 
by the time the Cretaceous period opened it had so far sunk that 
the Atlantic coast region south of Nets York was again exposed 
to the ocean, and flourished with abundant marine life, the 
Cretaceous fossils of the coast giving full evidence on this point. 
hus the absence from the present Atlantic border of all Tri- 
assic and Jurassic marine fossils and the presence of Cretaceous 
Species in great numbers are well accounted for. : 
Prof. unt has recognized the existence, on the Atlantic 
