The Geology of II Ingham. 19 



years. It was not until after the close of this age that the 

 Alleghany Mountains were elevated, bearing up with them the 

 Carboniferous matter which now makes up the great body of the 

 coal found in their strata. 



To the Carboniferous Age succeeded the Triassic, Jurassic, and 

 the Cretaceous Periods of Mesozoic Time, and the several periods 

 of the Tertiary Age in Camozoic Time. It was during the Creta- 

 ceous Period of the former, and the periods of tbe latter that 

 deposits were made along the eastern and southern shores of 

 North America, forming strata which by subsequent elevation 

 now compose a considerable part of the middle coast States, and 

 nearly the whole of those that border the Gulf of Mexico, and 

 it was, too, during these periods that a large portion of the strata 

 now composing the Rocky Mountains were formed beneath the 

 waters. These mountains did not attain to their present elevation 

 until near the latter part of the Tertiary Age. The Reptilian and 

 Tertiary Ages passed without leaving any traces now recognizable 

 on the territory of Hingham. 



We have now reached a period which has received the name of 

 Glacial, and which calls for particular notice, because nowhere 

 perhaps can results of the extraordinary phenomena attending it 

 be more readily seen than in Hingham. The extent of the change 

 made upon the whole surface of the land north of Pennsylvania 

 can never be fully realized, and it was probably as great over this 

 town as over a like area anvwhere. What were the distinguish- 

 ing characteristics of this period ? We have seen that in a pre- 

 ceding ao;e, when the coal of the threat coal-fields of the continent 



CO? O 



was laid down, the climate everywhere north was tropical. We 

 now find it to have changed to one of great cold, and that this 

 continued, if we may rely on the estimate made by Thomson, 

 more than 350,000 years. Life became extinct under its influ- 

 ence, and over nearly the whole land north of Pennsylvania there 

 came to be a covering of ice several thousand feet in thickness, 

 which, governed by the same influences that affect the great 

 bodies of ice in glacial regions at the present time, moved steadily 

 and majestically towards the south, throwing off icebergs where 

 it reached the sea, as is the case with the glaciers of Greenland 

 now, and gradually melting and thinning out as it approached 

 warmer latitudes on the land surface. 



Through the investigations of the Rev. G. Frederick Wright, 

 Mr. Warren Upham, and others, we now have certain knowledge 

 of a great part of the boundary line of the glacial sheet over the 

 land, from as far west as Illinois to the Atlantic, this being well- 

 marked by the morainic deposits of the debris brought from 

 northern regions in and upon the ice, and deposited at its margin. 

 Want of space will not permit the writer to dwell upon these, but 

 the reader is assured that their character cannot be mistaken. 

 The terminal moraine has a very irregular course east from Illi- 

 nois, passing through the States of Indiana, Ohio, a part of Ken- 



