326 Association of American Geologists and Naturalists. 
to those of Lyell and Murchison, yet he had relied mainly on the force 
of the polar currents. But as to the cause of these currents, which 
had been previously referred to, he desired to wash his hands of all sus- 
picion of attributing them to the melting of ice and evaporation in the 
lower latitudes. He considered them to be due to other causes of a 
far different nature. 
-»Mr. R. spoke of the vast effects of the regular polar currents ie the 
ocean in the transportation and deposit of bowlders and drift, cur- 
rents which must have been in action ever since the earth had rolled on 
its axis with an. incumbent ocean ; and he thought this mighty and endu- 
ring agency as conjoined with ice had not been duly appreciated. He 
felt that much credit was due to Mr. Hayes for the facts which he had 
collected from observant voyagers, and took occasion to allude to the 
summary outlines of the systematic currents of the ocean which had 
been given by himself at a former meeting of the Association, but not 
furnished for the report of proceedings. He then traced on the map 
the. natural course, as well as the deflected or forced direction of these 
currents as they issued from the Arctic regions ; the natural course fall- 
ing westerly and the deflected one easterly of a meridian line, and cor- 
ponding severally i in direction with each of the two systems of strie 
found on the rocks of North America. He showed on the map the 
coincidence of these strie with the present courses of the great ice- 
fields and numerous. icebergs of the north; suggesting that attention 
to the phenomena of single icebergs in open sea would fail to produce 
an adequate conviction of the efficiency of the cause in question. © But 
those who had attentively considered the narrative of the last voyage » 
of Capt. Back might be satisfied that the movements in mass of such 
vast packs of ice and icebergs as those in which his ship was enclosed 
for many months and moved slowly a great distance to the southward 
by the force of the great current and the agitation produced by storms, 
doubtless while rending and moving by means of the vast floes and the 
base of the bergs ,the incoherent portions of the shores and the suba- 
queous topography and grooving the faces of the coherent rocks, were 
causes which acting without stint of time, were sufficient to youn 
most of the phenomena which have been noticed in drift formations. 
Mr. Hayes said his observations had proven to his satisfaction 
that the immense mass of these icebergs below the water caused 
them to be entirely influenced by the currents beneath the sut- 
face, and ‘explained why apparently they were not affected by 
the winds and currents above the surface. He alluded to some 
facts which had been observed as illustrative of this point. — The 
eason of; these strong under-currents he did not undertake to x 
