The Geology of Hinghmn. 53 



Rocky Neck. — On a beach of the northern shore, upon diabase, 

 are glacial strise showing a direction southeast, and also cast of 

 south 80°. 



Union Street. — On the left side of Union street, 1670 feet 

 from Lascll, and just beyond Long Bridge Lane, is a granite ledge 

 upon which are numerous striae. 



Summer and Rockland streets. — Just at the corner of these 

 streets, by the roadside, is an exposure of diabase trap, before men- 

 tioned when treating of dikes, upon which are striae which show 

 variation in direction as follows : — 



East of south 10° 

 East of south 12° 

 East of south 15 D 



Weir Street. — On the right side of the roadway of this street, 

 a short distance from the railroad-crossing, is an exposure of dio- 

 rite showing striae running — 



East of south 5° 

 East of south 1CP 



INDIAN POT-HOLES, OR GIANTS' KETTLES OF 

 FOREIGN WRITERS. 



It is well known that wherever there exist waterfalls of any mag- 

 nitude, pot-holes, so-called, are often found beneath the rushing 

 waters, formed by the friction of stones which have been lodged 

 in the hollows of the rock surface over which the torrent pours, 

 and which, having a somewhat circular motion imparted to them, 

 gradually wear away the rock, with the result of producing these 

 singular objects. 



It is not surprising that when these have been found, as has often 

 been the case, where there was nothing to indicate there had ever 

 been a river or running stream, they should have excited alike the 

 wonder and interest of both scientific and unscientific beholders. 



It should be borne in mind that the knowledge of a great conti- 

 nental ice-sheet resting over our whole northern region is but a re- 

 cent acquisition, and that phenomena having their origin under such 

 a condition of things could not possibly be understood previously 

 by the most learned of observers. 



' The ideas of the unlearned respecting such pot-holes are often 

 ludicrous. With our own people they have been regarded as the 

 work of the Indians, and where found have been called Indian Pot- 

 Holes, from the thought that they had been wrought for and used 

 as cooking vessels. Abroad they have been called Giants' Kettles, 

 undoubtedly from the belief that they were made by giants for 

 their culinary use. 



The study "of glacial phenomena within a few years has thrown 

 a flood of light upon much that was before obscure, and we now 



