1876.] 279 [Niles. 



large areas of unbroken rock are exposed to the sun, an expansion 

 attends the increase of temperature. Probably certain movements, 

 not mentioned here, are precipitated, and perhaps caused by the 

 heating of the surface, but the origin of the phenomena designated 

 cannot be ascribed, consistently, to changes of temperature so long 

 as the features produced do not perceptibly vary with such changes. 



OBSERVATIONS AT OTHER LOCALITIES. 



I am informed by one of the proprietors of the quarry of Warren 

 Gates' Sons at Waterford, Conn., that slight movements of the rock 

 have been there observed under the following conditions. In using 

 the steam drill for cutting out blocks of stone from the rock in place, 

 if the holes are made very near each other the small portions of stone 

 thus left between them are often crushed, and the drill so pinched 

 that it cannot be worked. They also observe that the pressure is 

 limited in its action to a northeasterly and southwesterly direction. 

 The quarry is located a little east of south from Monson, at a distance 

 of nearly sixty miles in a direct course. The stone quarried there, 

 commercially known as Millstone Point Granite, is a gneiss, which 

 although differing somewhat in external appearance from the Monson 

 stone, is of similar constitution and texture, and occurs under similar 

 geological conditions. 



In the town of Groton, Conn., which is situated upon the left bank 

 of the Thames River, opposite Waterford and New London, I ob- 

 served evidences of pressure upon some thin sheets at the bottom of 

 one of the small quarries, but the conditions did not admit of further 

 determination. Although I have not as yet been able to give that 

 study to this district which the importance of the subject demands, 

 I have thought it best to present the information because it so 

 perfectly accords with the better observed phenomena at other 

 localities. 



I would also refer again to the observations of Professor Johnston, 1 

 at the sandstone quarries of Portland, Conn., which led him to con- 

 clude that the " sliding of one stratum up:>n another " there observed, 

 was " apparently in consequence of an immense lateral pressure," 

 and that this pressure was in a northerly and southerly direction. 



i Proc. Am. Assoc. Adv. Sci., Vol. VIII, p. 285. 



