20 History of Hingham. 



tucky, Pennsylvania, and New Jersey, reaching the ocean at Perth 

 Amboy, where it is lost to sight. It is not difficult, however, to 

 trace the limit of the ice sheet east from the land. The evidence 

 by morainic deposits shows its front at one period to have been 

 over Long Island, Martha's Vineyard, and Nantucket, from which 

 it unquestionably extended far out over the ocean in a northeast 

 direction, the shallowness of the waters at the Great Fishing 

 Banks being due to the immense deposits from the glacier. 



What brought about the great change that converted a large 

 area of the earth from one teeming with life to one where the 

 silence of death reigned supreme, we may never certainly know. 

 If not due entirely to the elevation of the land in the northern 

 regions of the earth, which occurred in the later Tertiary Age, 

 there can be no doubt but that this was a potent factor, for the 

 Glacial Period was one of high latitude elevation ; nor can we 

 fully account for the great subsecjuent reconversion of the same 

 area, or much of it, to become again the abode of life after long 

 ages of desolation. It is only with the results of the action of the 

 ice upon the surface of the land that we have now to concern our- 

 selves, and it is absolutely necessary to understand these in order 

 to have the slightest appreciation of observed phenomena in Hing- 

 ham as well as elsewhere over the North, consequent upon the 

 great ice movement during the long period of its domination. 

 One certainly was the bearing forward of a great part of all the 

 loose material beneath its mass formed by the disintegration of 

 the rocks, and redistributing it on the line of its advance south. 

 Hence, a considerable portion of the rocky masses, bowlders, and 

 pebbles, as well as of the gravelly and sandy material in which 

 they are imbedded, now forming the surface upon the hills and 

 fields of New England, have been borne from the North ; and 

 whenever such bowlders and pebbles are of marked character, 

 they can generally be traced to the locality of their formation. 

 A good instance of this is seen in the bowlders and pebbles of 

 porphyritic iron ore, found everywhere between Cumberland Hill, 

 R. I., and the shores of Rhode Island, south, all on the line of 

 the ice movement, — the masses, as might be expected, being 

 generally of smaller and smaller size as the distance increases 

 from their source, where a great bed of this peculiar ore exists 

 in situ. The quantity of earth-substance moved forward over 

 the surface must have been enormous, as is shown by the fact 

 that many of the hills of the glaciated territory are composed en- 

 tirely of it, and in the southeast of this State, over a large area, 

 the rocky strata are buried beneath a covering of it to the depth 

 of three hundred feet. Another result of the movement w r as the 

 wearing down, the planing, so to speak, of the rocky surfaces ex- 

 posed to the great friction of the detrital material carried forward 

 under the mass of the superincumbent ice. Whenever bowlders 

 such as are seen everywhere in our New England soil, or 

 even large pebbles, were torn off from the places of their origin, 



