Association of American Geologists and Naturalists. 323 
the sea level, and brought the detritus above the surface. During the 
periods of tranquillity marine shells were deposited in those portions 
of the country which were submerged. Durocher, De Beaumont, and 
Bohtlink, all consider the glacier theory insufficient to produce the 
effects observed. And the phenomena in Scandinavia, like those ob- 
served here, all go to disprove the hypothesis of Agassiz. Even in 
Switzerland, the celebrated Prof. Andre De Luc regards the views of 
Agassiz as fanciful and imaginary. Dr. J. referred to the quotation of 
Peter Dobson’s hypothesis by Mr. Murchison. He concluded by re- 
marking that he had travelled over most of the Swiss glaciers, and 
knew the statements made were greatly exaggerated. He knew too 
that our drift strize and erratic blocks did not radiate from one principal 
mountain group, nor were they in any case much deflected by them ; 
nor was there any proof that glaciers had ever existed in Maine, New 
Hampshire, or Massachusetts. 
Mr. Nicollet then rose and addressed the meeting at conside- 
rable length and with great animation on the subject of Dr. 
Jackson’s paper just read, and in opposition to the glacial the- 
ory of M. Agassiz. He expressed his astonishment that M. 
Agassiz should have entirely overlooked the labors of his prede- 
cessors in the same field, and particularly of M. De Saussure, who 
spent forty years in investigating all their phenomena, and had 
nearly exhausted the subject. It was impossible to conceive how 
the effects ascribed by M. Agassiz to the moving glaciers could 
with propriety belong to them. The mer de glace was an im- 
mense vault of ice under which, as in a grotto, one could walk 
even for twenty miles, while on its bottom runs a stream of wa- 
ter. How could the bottom of the mer de glace then be suppos- 
ed to score and furrow the rocks in its path? M. Agassiz had 
overlooked too the true effect of the expansion of the ice; he 
had ascribed to 7¢ the downward movement of the glacier, while 
De Saussure long ago proved that this motion was due to gravity 
only. ‘The expansion did effect the fissuring and arching up of 
the glacier, just as it produces the same phenomena in the ice of 
our rivers. 
One very important point in the subject of diluvial furrows 
had been overlooked by M. Agassiz as well as by many other 
observers of the same facts, not only in the Alps but in other 
places—this was whether the furrows on the rocks obeyed the 
direction of the valleys, or the general direction of diluvial fur- 
rows, irrespective of the sides of mountains and the course of 
