1885.] XEW YORK ACADEMY OF SCIENCES. 79 



in diameter — really boulders, such as could not have been trans- 

 ported far from their place of origin, and could certainly not 

 have been derived from any mid-Alan tic continent. The Orisk- 

 any sandstone, the Medina and the Potsdam, which are the 

 shore deposits and bases of the Devonian, and Upper and Lower 

 Silurian systems, are nearly as thick and coarse along thcAvestern 

 Hank of the Blue Ridge, the old land of the Alleghany belt. But 

 the representatives of the same strata in New England are much 

 thinner, and generally finer, though deposited nearer to the im- 

 aginary Atlantis. 



The fact is that a belt of high land occupied in part the place 

 of the Alleghanies from Archasan times. From its surface, as 

 we know by indisputable evidence, not less than four or five 

 miles of material have been removed, and by drainage lines and 

 the advance and recession of shore waves, spread inland toward 

 the center of the Mississippi valley. The quartz veins of the ero- 

 ded metamorphic rocks furnished the conglomerates and the 

 sandstones; the argil) ites and schists made the shales of each 

 system; and these sheets of land-wash diminish in thickness as 

 we recede from their place of origin. So the Canadian High- 

 lands, with the Adirondacks and Lake Superior region, formed 

 another land area in Palaeozoic times, from which the wash was 

 spread southward, in sheets of diminishing thickness. The same 

 is true of the old land of the far west. The Potsdam sandstone is 

 as thick and coarse around the Black Hills and along the 

 flanks of the Rocky Mountains and the Wasatch, as anywhere in 

 Canada, New York, or Virginia. 



European geologists are best qualified to discuss the applica- 

 tion of Professor Hull's theory to European geology; but speak- 

 ing only from my own knowledge of American geology, I can say 

 that the facts here not only do not sustain, but positively dis- 

 prove it. It would be only necessary for a geologist as sagacious, 

 experienced, and honest as Professor Hull, to make even a hur- 

 ried reconnaissance of the structure of eastern North America to 

 be convinced, and to confess that it here finds no support. 



The recent earthquake waves felt on the Pacific coast, and the 

 remarkably high tide upon the Atlantic coast, were the subject 

 of discussion by Prof. Martijst, Prof. Trowbridge, and Dr. 



JULIEN". 



