Association of American Gteologists and Naturalists. 333° 
and loose fragments of hard rocks, mixed with smaller gravel and 
sharp sand. cote ah o HR AS a ge 3 
_ B. Silliman, Jr. stated that much of the loose material which 
covered the red sandstone of Connecticut, consisted of fragments 
of rocks, many of which could be referred to the trap mountains 
to the north, which presented one surface worn down quite flat, 
like the rubbing stone of a stone-cutter, and as if they had been 
carried evenly and for a long time, over the surface of the rocks, 
by some force competent to keep them in one position. He left 
it for gentlemen to decide as best suited their own views, whether 
they were thus held by being set in ice, or by a superincumbent 
and adjacent mass of loose materials and waters. The large peb- 
bles of quartz and other hard rocks, of which the coarser beds of 
conglomerate in the Connecticut valley were composed, were 
worn down without dislocation, and had, measurably, served to 
protect a dee of adjacent rock from degradation in a manner simi~ 
lar to the cherty nodules shown by Mr. Hall. The striations in 
these valleys were about 8. 20° E. and were on the whole irre- 
Spective of the directions of the valley, frequently scouring the 
sides of hills, in a line oblique to the axis of the valley. 
The Chair urged that the diluvial currents had extended far- 
ther to the south in the long parallel valleys of Pennsylvania, and 
had been much influenced by the existing topography of the 
country ; and the scourings on the rocks there were resultant 
lines between the general direction of the onward current, and 
the direction of the mountain slopes. It was uninfluenced by 
the topography of the country so long as the waters stood above 
the summits of the mountain ridges, but when the inundation 
was nearly exhausted, the subdivided current conformed itself 
almost entirely to the configuration of the surface. ene 
- Mr. Redfield said that the diluvial markings on our American 
rocks, might be viewed as constituting two distinct systems, in 
one of which the strice have a southwesterly direction, in the oth- 
er a southeasterly one ; the latter system greatly predominating 
in the country lying east of the Hudson. is 
The discussion was continued for some length by Messrs. 
Houghton, Jackson, Espy, Rogers, Hitchcock and Hall, and it 
was generally admitted that we must find, in the conjoint action 
‘water, ice and loose detritus, a cause sufficient to account for 
all the phenomena known by the various names of glacial, dilu- 
vial and aqueo-glacial. 
