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slate and the fact that the conglomei-ate and isandstone are less 

 generally indurated through intimate association with the 

 volcanic rocks, the sedimentary rocks ot" Hinghani are less 

 prominent, topograpliically, than those ot Nantasket. The 

 slate, where occurring in large bodies, is very generally eroded 

 nearly to or below the present level of the sea, while the con- 

 glomerate and melaphyr are found mainly below the contour of 

 forty feet, and never rise much if any above seventy feet, attain- 

 ino- tlieir i^-reatest elevation in the ridii^e alonijj South Street in 

 llingham Village. The granitic area, on the other hand, is, as 

 a whole, somewhat more elevated than in Cohasset, owing prob- 

 ably to its greater distance from the sea ; the average or normal 

 elevation of the ledges south of the railroad ranging, probably, 

 from 60 or 70 feet to nearly or quite 150 feet in the south part 

 of the town. Although the hard rocks thus show, from the 

 lowest slate to the most elevated ledges of granite, a notable 

 range in altitude, tiiere are, properly s[)eaking, no rock hills 

 except such as have resulted from the division of the peneplain 

 and its reduction to a fragmentary condition by glacial erosion. 

 Especially do we note the absence, as in Cohasset and Nantasket, 

 of dominant rock hills or those decidedly overlooking the [)ene- 

 plain. The characteristic features of an ancient topography — 

 well-defined ridges with culminating summits separating broad 

 level valleys — are wanting here and in Cohasset and through- 

 out this region ; but we find instead the comparatively narrow 

 and abrupt valleys and the. broad, plateau-like, interstreani 

 surfaces indicative of a region which, having been worn down 

 to its base-level, has found a renewal of its topographic life in 

 a comparatively recent elevation and is only now well started 

 in a new cycle of topographic development. This topography 

 is geologically ancient only in the sense that it starts, not from 

 an elevated sea-bottom, a virgin land-surface, but from an 

 elevated peneplain, itself the last expression of an earlier 

 topography ; and if the present stability of the land continues, 

 the features of the modern topography will, after attaining a 



