154 
GEOLOGY OF NORTH CAROLINA. 
Three periods are distinguishable in this formation in North Carolina, 
the Glacial, Champlain and Terrace ; the first two quite readily. 
Glacial . — Over the more eastern parts of the formation, where the 
elevation above tide does not exceed about 100 feet, there lies upon 
eroded surface of the underlying Eocene, Miocene or Cretaceous, a thin 
stratum of a few inches to a foot, (rarely more), of tolerably coarse 
pebbles, often with shark’s teeth, coprolites and rolled fragments of bones, 
washed from the older rocks; and along the river bl lifts, notably of the 
Cape Fear, this stratum, which lies frequently in a level line for hun- 
dreds of feet just above the water's edge, consists of a single layer of scat- 
tered pebbles and bowlders, often a foot and more in diameter, on a smooth 
floor of Cretaceous, for example. The underlying rock was evidently 
planed down by the currents and drifting ice which carried these bowl- 
ders from the Archaean hills of Chatham, to which they are readily 
traceable. And this erosion of the surface and scooping out of the broad 
river valley no doubt took place during the Glacial period , or the earlier 
part of the Quarternary age, which was a period of elevation in this part 
of the Atlantic slope, in common with the more northern portions of the 
continent, as is evident from the fact that the bed of the Cape Fear at 
Wilmington, for example, was grooved down to a depth of about 100 feet 
below the present sea level. This has been shown both by excavations 
and pile driving ; the latter being carried down to the depth mentioned, 
through the peaty alluvion which has filled up the old bay-like 2 miles 
breadth of the river at this point, and reduced it to about 100 yards, and 
the excavations having brought up, from a depth of 70 feet, huge trunks 
of cypress trees, together with just such bowlders of Chatham rocks as 
those along the higher reaches of the river, as above described, some of 
these stones being more than a foot through. ’ This stratum of pebbles 
between the older formation and the Quarternary often contains fossils, as 
previously stated, in the torm of teeth, bones, coprolites, Ac., but rounded 
and worn, evidently derived from the denuded underlying formation, 
Tertiary or Cretaceous. 
Here, however, have been found the best preserved and entirely un- 
worn specimens of Mastodon teeth and bones, possibly derived from 
the preceding formation, but from their mechanical condition, almost 
certainly belonging to the beginning of the Quarternary age or the 
Glacial Period. 
Further evidences of a Glacial period in this latitude will be presented 
further on, in the Quarternary of the piedmont and mountain regions. 
Champlain . — Along the bluffs of the Cape Fear below Fayetteville, 
one of the most persistent and regular beds is the sand and gravel de- 
