28 PROCEEDINGS OF THE ASSOCIATION OF 



the various terraces of our rivers seem to present the same phe- 

 nomena ; for the source of tliese elevatory movements we must 

 look to the gi'cat volcanic foci of Greenland. 



Prof. Locke mentioned a locality in Ohio, at which the lime- 

 stone is ground down to a perfect plane, as if it had been done 

 by a stone-cutter by grinding one stone on another, over an extent 

 of ten acres. Upon this planished surface, lines have been en- 

 gi'aved in systems perfeclly straight and parallel, running from 

 northwest to southeast. Some of these lines are fine, as if cut 

 with the point of a diamond, and others perhaps half an inch 

 broad, and one eighth of an inch deep, scaled rough in the bot- 

 tom, as if they had been ploughed by an iron chisel properly set 

 and carried forward with an irresistible force. Prof. L. inferred 

 from the facts of the exact straightness and parallelism of these 

 lines, that they had been formed by a body of immense weight, 

 moving with a momentum scarcely affected by the resistance 

 offered by the cutting of the grooves. Such a momentum and 

 actions would be supplied by a floating iceberg, Avhose lower 

 surface should present projecting sharp points of imbedded bowl- 

 ders. 



Prof. Mather further stated, that the bowlders of Ohio were 

 in continuous lines and groups, and not scattered promiscuously. 

 On the river St. Peters, the bowlders may be seen extending for 

 miles, as along a coast line ; in some situations one might see 

 them bounding the horizon as far as the eye could reach. 



Dr. Locke, in conformity with Prof. Mather's statements, men- 

 tioned a region of bowlders in Ohio, extending from the town of 

 Eaton quite across the State ; five miles in width and over forty 

 in extent. 



Dr. C. T. Jackson remarked, that the phenomena of diluvial 

 currents were well exhibited in the vicinity of Providence, at 

 Cumberland, R. I. A large mass or mountain of porphyritic 

 titaniferous iron, of very peculiar character, exists in that place ; 

 to the north of it no bowlders are to be found, but on the south, 

 huge bowlders of it may be seen, and so abundant that the stone 

 walls are built of them ; and below, at Papoose Squash Neck, 

 small bowlders of the same characteristic rock are found ; south 

 of Newport, and still further south, the same are met with of a 

 smaller size, the whole extending from north to south forty miles, 

 and from six to fifteen in width, diverging to tlie south. 



The characteristic made rock at Lancaster, Mass., presents 

 similar phenomena, being found in loose masses to the south as 



