CHAPTER I. 



THE RELATIONS OF THE GEOLOGY OF NEW HAMPSHIRE TO THAT OF 

 THE ADJACENT TERRITORY. 



BEFORE discussing the particulars of the geology of New Hamp- 

 * shire, it will be desirable to recall the general features of the 

 geological structure of the continent, in order to properly understand 

 our place upon it. Next, we shall turn our attention to the physical 

 characteristics of that particular section of which we find ourselves an 

 important component; and then examine more minutely the various 

 groups of strata peculiar to our district. It will be to the latter topic 

 that we shall devote the most attention. 



Continental Subdivisions. 



North America is rudely triangular in shape, with its most prominent 

 mountain ranges adjacent to the eastern and western borders, the latter 

 being the broadest, highest, and opposite the larger ocean. The rocks, 

 so far as needful for our present purpose, may be classified as the crys- 

 talline, two sets of sedimentary sandstones, limestones, and shales, and, 

 lastly, the loosely-coherent superficial formations occupying various basins 

 and water margins underlaid by the more compact ledges. These four 

 groups correspond in order with the Eozoic, Paleozoic, Mesozoic, and 

 Cenozoic systems of geological authors, the first being the oldest, or that 

 first reclaimed from the universal ocean. 



In order to illustrate the relative positions of these four classes of 



