136 Barrel! — Growth of Knowledge of Earth Structure. 



" 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 

 of the country. In this case, the disturbing force must have 

 acted beneath the primary rocks. And besides, we have good 

 evidence which will be shown by and by, that our new red 

 sandstone was formed beneath the ocean. We cannot then 

 reason on this subject from present levels." 



In 1840, H. H. Rogers, a geologist who has acquired a 

 more widely known name than Hitchcock, but who in 

 reality showed an inferior ability in interpretation, made 

 the following 1 statements in explanation of the regional 

 monoclinal dip of the New Jersey Triassic rocks averag- 

 ing 15 to 20 degrees to the northwest -} 



' ' Their materials give evidence of having been swept into this 

 estuary, or great ancient river, from the south and southeast, 

 by a current producing an almost universal dip of the beds 

 towards the northwest, a feature clearly not caused by any 

 uplifting agency, but assumed originally at the time of their 



1 H. D. Rogers, Geology of New Jersey, Final Report, p. 115, 1840. 



