156 A CENTURY OF SCIENCE 



ing the slow settling of opinion may be cited in regard to 

 the significance of the dip of the Triassic formations of 

 the eastern United States. The strata of the Massachu- 

 setts-Connecticut basin possess a monoclinal easterly dip 

 which averages about 20 degrees to the east. Those of 

 the New Jersey-Pennsylvania-Virginia basin possess a 

 similar dip to the northwest. Both basins are cut by 

 great faults and the dip is now accepted by practically 

 all geologists as due to rotation of the crust blocks 

 away from a geanticlinal axis between the two basins. 

 Edward Hitchcock, whose work from the first shows an 

 interpretative quality in advance of his time, states in 

 1823 (6, 74) regarding the dip of the Connecticut valley 

 rocks : 



"There is reason to believe that Mount Toby, the strata of 

 which are almost horizontal, exhibits the original dip of these 

 rocks, and that those cases in which they are more highly inclined 

 are the result of some Plutonian convulsion. Such irregularity 

 in the dip of coal fields is no uncommon occurrence." 



In Hitchcock's Geology of Massachusetts, published in 

 1833, ten years later, geological structure sections of the 

 Connecticut Valley rocks are given, the facts are dis- 

 cussed in detail and the dip ascribed to the elevatory 

 forces. He says (1. c., pp. 213, 223) : 



"If it were possible to doubt that the new red sandstone 

 formation was deposited from water, the surface of some of the 

 layers of this shale would settle the question demonstrably. 

 For it exhibits precisely those gentle undulations, which the 

 loamy bottom of every river with a moderate current, presents. 

 (No. 198.) But such a surface could never have been formed 

 while the layers had that high inclination to the horizon, which 

 many of them now present : so that we have here, also, decisive 

 evidence that they have been elevated subsequently to their 

 deposition. . . . 



The objection of a writer in the American Journal of Science, 

 that such a height of waters as would deposit Mount Toby, must 

 have produced a lake nearly to the upper part of New Hamp- 

 shire, in the Connecticut Valley, and thus have caused the same 

 sandstone to be produced higher up that valley than Northfield, 

 loses its force, when it is recollected that this formation was 

 deposited before its strata were elevated. For the elevating 

 force undoubtedly changed the relative level of different parts 



