244 The American Geologist. April, i89i 
On page 112 of his report, Prof. Rogers first makes mention of 
the associated limestones and sandstones, and as he calls it, 
sienitic granite. He however is a little ambiguous for he speaks 
of it as a bed of sienitic granite of the usual composition of the 
gneiss of this region, which dips eastward with the other beds, 
i. e. the white limestones, gneiss and sandstones. 
He speaks of the scarcity' of organic remains but states that he 
found madrepores in proximity to the flint}' nodules in the 
limestone. 
He says nothing in this report of his idea of the cotemporaneous 
origin of the white and blue limestones, but as he describes this 
altered under the head of Formation II, one is at a loss to decide 
as to what his attitude was on the question. 
His section through this point, though, shows the blue lime- 
stone and sandstones dipping N. TV. , the gneiss, beds of frank- 
linite and altered limestone or marble with veins of quartz and 
sienite dipping S. E. Then the blue limestone which is again 
represented as dipping N. TV. 
His only marked error in this section is in representing the 
blue limestone as keeping its N. TV. dip to Hamburg Mt. , whereas 
the N. TV. dip is in a short distance succeeded by a S. E. dip, and 
then the reappearance of the white limestone which reaches nearly 
to the mountain to the east. 
In the "Final Report on the Geology of N. J.," published in 
1840, on pp. 47 to 67, Prof. Rogers describes the limestones of 
Formation II. In these pages the geological features are outlined 
with such boldness and fidelity to fact as to awaken in one the 
feelings of profoundest admiration for one who could accomplish 
so much with the limited time and means at his disposal. Under 
the title "Formation II," Prof. Rogers describes in detail the blue 
limestones, "called in N. J., magnesian, in N. Y. calciferous. " 
In these pages he makes no special mention of the white lime- 
stones, but from the locating of isolated patches of Formation II, 
especially in the low water shed between the Musconetcong and 
the TVallkill rivers, it becomes very evident that there is no shadow 
of doubt in his mind but that the two limestones are cotempora- 
neous in origin. 
It is under the heading of < ' Igneous Rocks Connected with For- 
mation II," that all ambiguity is removed and his position is 
clearly and positively defined. That there may be no possibilit}' 
