98 National Geographic Magazine. 
tle slope of the newly revealed Cretaceous cover. It was at that ~ 
time a compound, composite river :* compound because it drained 
areas of different ages ; composite, because these areas were of 
different structures. Existing examples of compound, composite: 
rivers are seen in the Catawba, the Yadkin-Pedee, the Cape Fear 
and the Neuse rivers of North Carolina, which all rise on the 
inland crystalline area, and traverse the coastal quaternary plain 
before reaching the sea. But unlike these, there must have been, 
when the old submerged land rose with the Cretaceous cover on 
its back, numerous small streams whose drainage area lay entirely 
within the Cretaceous plain. These were simple streams, flowing 
over a structure of one kind and one age. Their modern homo- 
logues are seen in the Maurice, the Great and Little Egg Harbor 
and the Wading rivers of southern New Jersey, and I suppose 
also in various relatively short streams of North Carolina, such as 
the Lumber, Great Cohera and Moceassin. 
It cannot be supposed that the original Pequannock-Passaic 
possessed the large southern branch, which I shall call the upper 
Passaic, by which Great Swamp is now drained ;+ for had this 
been the case, the divides between the branches of the upper 
Passaic and the heads of the small streams that now still cross 
both of the trap ridges, must have long ago been driven to a 
stable position on the crest line of the inner ridge. The upper 
Passaic member of the Pequannock-Passaic system must be re- 
garded as a branch of subsequent development, guided by some 
of the softer Triassic beds when they were reached beneath the 
Cretaceous cover, and very successful in capturing and diverting 
other transverse streams that were smaller than its master. For 
some distance on either side from the Pequannock-Passaic gap in 
the trap ridges at Patterson, the existing streams are perfectly 
adjusted to the Triassic structure ; that is, the ridges are persis- 
tent divides, and the lateral subsequent branches of the master 
flow along the strike of the softer shales and sandstones, except 
where lately thrown off their courses by glacial drift barriers. 
This I interpret as meaning that the Pequannock-Passaic master 
*See terminology suggested. by the author. Nat. Geogr. Mag., i, 
1889, 218. 
+ It should be recognized that the present round-about drainage of the 
Great Swamp is a post-glacial feature, determined by the morainic bar- 
rier that crosses the basirt from Summit (S) to Morristown (M): the pre- 
glacial drainage of the southern part of the inner crescent was un- 
doubtedly of a simpler and more direct pattern. 
