Hatteras Axis in Triassic a)id in Miocene Time. — Glenn. 375 
THE HATTERAS AXIS IN TRIASSIC AND IN 
MIOCENE TIME. 
By L. C. Glenn, Baltimore, Md. 
In a recently made study of the Triassic of eastern North 
America certain Hthological, structural, and dynamical facts 
were found so grouped as to point to the existence of the 
southern Virginia-North Carolina Triassic reg-ion as an area 
of maximum stability, or of minimum movement, during 
Triassic time. Also investigations now in progress by the 
writer on tht paleontology of the Miocene of the Carolina re- 
gion, show that it was a land area during early and perhaps 
middle Miocene time and was then submerged by a marked 
transgression of the sea westward across this land area when 
later Miocene deposits were laid down upon it. 
So far as is known these facts have not heretofore been 
recognized. They are deemed of enough physiographic im- 
portance to warrant a brief statement. With them will be 
briefly noted the evidence bearing on the same problem fur- 
nished by the other coastal plain formations of the region. The 
treatment will follow the order of the succession of the forma- 
tions involved. 
In the Triassic of the Connecticut valley region, as is shown 
by Prof. Davis,* there is strong evidence in the cross-bedding, 
ripple marking and coarseness of the deposits and in the mud 
cracks, rain drops and footprints found through such a great 
vertical thickness of the deposits, to show that during the time 
of Triassic deposition in that region deformation was in active 
progress, and subsidence was constantly going on. These 
deposits, mainly coarse and all quite near the land from which 
they were derived, must have been laid down comparatively 
rapidly; and while the basin was ever almost filled, yet the sub- 
sidence was so rapid it was never quite full. 
The same conclusion as to deformation and subsidence 
is reached by another line of evidence. While in the Connecti- 
cut Triassic impressions of large strap-shaped leaves, pieces 
of tree trunks and even some carbonaceous shale are found, 
yet deposits of coal are wanting, showing that at no time did 
subsidence cease long enough or progress slowly enough to 
*i8th Ann. Rept. U. S. GeoL Sur., Pt. II, p. 34 and £fg. 
