in Rocks and Recent Rock Flexures. 411 



forced up the shale as a viscous mass aud so breaking the lime- 

 stone bed above it. 



It is evident, however, that this explanation will not meet 

 the cases mentioned by Professor W. H. Mies where the phe- 

 nomenon of lateral pressure he describes have acted over a 

 considerable area and under diverse conditions of rock struc- 

 ture.* 



At Monson, Mass., the quarry was in a belt of gneiss lying 

 east of the red sandstone of the Connecticut Valley. The 

 strike of the gneiss is north 10° east and the dip 10° north at 

 the high angle of 80°. The pressure as seen by the move- 

 ments of the beds in the quarry appears to have been parallel 

 to the strike or at right angles to the movement that originally 

 flexed the beds. 



At Berea, Ohio, the quarries in which movement was 

 observed are in sandstone (Berea grit of the Waverley group), 

 lying nearly horizontal and the movement was in a north and 

 south line. 



At Lemont, Illinois, the quarries were in the Niagara lime- 

 stone and an anticlinal axis was formed striking east and west 

 800 feet in length and rising from 6 to 8 inches in the most 

 conspicuous parts. " It was formed along the line of vertical 

 joint which extends beyond the limits of the quarry. The con- 

 tinuous edges of the bed were bent upward, making an eleva- 

 tion which was a little more upon the north side of the joint 

 than upon the south and a slight fault was in this way pro- 

 duced." Another quarry referred to is at Waterford, Conn., 

 in gneiss, and another quoted from Professor Johnston is in 

 sandstone at Portland, Conn. Professor J. Johnstonf says that 

 these sandstone quarries are of great extent and 120 feet deep 

 from the original surface of the ground. A groove about a 

 foot wide and 80 feet long was being cut in a bed about 6 or 7 

 feet thick and in an east and west direction parallel to a 

 natural joint. When the channel had been sunk to within 

 about 9 inches of the bottom of the strata the remaining stone 

 was crushed to fragments with a loud report and the walls of 

 the groove had approached each other within about three- 

 quarters of an inch. Other similar movements occur and these 

 take place in a northerly and southerly direction and not in an 

 easterly and westerly line. 



In explanation of the Lower Fox River uplift, Mr. Cramer 

 calls attention to the suggestion of Mr. Gilbert that such-like 

 movements may have arisen from the expansion of the rocks 



* The geologic agency of lateral pressure exhibited by certain movements of 

 rocks. Proceedings of Boston Soc. of Nat. Hist., vol. xviii, 1876. 



f Proc. of the American Assoc, for the Advancement of Science, Eighth Meet- 

 ing, (1854). 



