334 Association of American Geologists and Naturalists. 
B. Silliman, Jr. then made a few remarks on the configura- 
tion of the valleys of the secondary, as influenced by and con- 
nected with the intrusion of trap rocks. 
The subject of appointing a committee on drift, to report at 
our next meeting, having come up for discussion, it was 
Resolved, That the following gentlemen be instructed to re- 
port on the present state of our knowledge on the subject of drift. 
New England and New York, Prof. E. Emmons; the West and 
far West, J. N. Nicollet; the South, W. B. Rogers; 
The chairman explained to the meeting, a view which had 
occurred to him to account for the crescent-formed dykes of trap 
in the new red sandstone of New Jersey and Connecticut. 
That the crescent form of the trappean dykes of the New Red sand- 
stone regions of New Jersey and Connecticut is in some manner con- 
nected with the dip of the stratified rocks which they traverse, is plainly 
indicated by the constant dependence between the direction of these 
crescents and the direction of the dip. Thus in New Jersey, where 
the dip of the Red Sandstone is towards the northwest, the horns of the 
crescents point towards the same quarter, while in Connecticut, where 
the strata. possess an easterly dip, the points of the crescents are direct- 
ed eastward. pls 
~ May we not explain this curious relationship by conceiving the fissure 
through which the melted trap has pushed to the surface, to conform 
itself, where it traverses the upper part of the inclined sandstone, to 
the plane of the dip. The sandstone being disrupted in a plane par- 
allel to the dip, the beds on the upper side of the sloping dyke will be 
lifted off from those upon which they reposed, and in this tilting of the 
beds, there will arise towards the extremities of the fissure seams oT 
transverse cracks, extending in the direction of the dip. Now when 
we view the outline of the principal or central portion of the fissure 
continued into these transverse cracks at its extremities, we readily pet 
ceive that it must constitute a curve or crescent concave in the direc- 
tion of the dip. ~~ Ai Cee 
_ Mr. B. Silliman, Jr. remarked that there was an almost pet 
fect identity between the views just explained by Prof. Rogers 
and those arrived at more than two years since by his friend Dr. 
James D. Whelpley and himself in the Connecticut valley. 
These views had been laid before Mr. Lyell, by Dr. Whelpley; 
and illustrated to Mr, L. by visits to several localities in the vicin- 
ity of New Haven. It had been their intention to lay a paper 0B 
the subject before the present meeting, but they would postpone 
it to next year. It was then 
