GEOLOGY AND SCENERY OF NORTHEAST COAST 97 



Ice Tickle Island or Rodney Mundy Island and cast his 

 eye over the singularly varied landscape. Under his feet 

 the observer will find the black ledges of trap. He speedily 

 notes that all the rounded ridges or knob-like hills of the 

 region have the same dark hue, and rightly concludes that 

 they are composed of the same rock. Between the hills 

 are short, broadly flaring valleys floored with light gray 

 schistose rock peeping out through the moss or from 

 beneath the curlewberry bushes and willows. Each of 

 the two large islands, for about three-quarters of its surface, 

 is underlain by the coarse-grained schists with some com- 

 mon granite. The remaining fourth of the surface is un- 

 derlain by the trap. Many of the ancient fissures have 

 parallel walls which are from ten to a hundred feet or more 

 apart ; others have doubly convex walls converging at the 

 two ends of gigantic pods of trap up to a thousand feet in 

 breadth and perhaps of twice that length. The trap being 

 more resistant to the weather than the rocks it cuts, the 

 hills have assumed the varying outlines of palisade, ridge, 

 or dome, according to the shape of their respective bodies 

 of intrusive rock. Such a landscape most tellingly declares 

 the fact that in mountains generally, but especially in old 

 mountains, the expression of the actual relief is really 

 more controlled by the age-long sculpturing of the elements 

 than by the original upheaval of the earth's crust. The 

 uplift and folding together of strata but furnished the raw 

 material ; the carving out of valleys by the weather, and 

 particularly the destruction of the softer rock-belts, leaving 

 the more slowly wasting, harder ones projecting, have 

 evolved the finished product, the mountain topography 

 of the present day. 



