24 THE POST-PLIOCENE. 



dor, but those which are known offer precisely the conditions required 

 for tlie accurauhxtion of boulder clays or drift by the action of pan 

 ice." 



"The seaward extension of Uksuktak Fiord, which lies a little to 

 the south of Hopedale, affords an apt illustration. Commander 

 Maxwell's soundings show a profound submarine ravine between 

 clusters of islands for upwards of eight miles, in which the depth 

 reaches 124, 126, 123, 106, and 130 fathoms. Between the islands 

 of Niatak and Paul, near Nain, the lead shows 71 fathoms. It is 

 evident that the material torn from the surrounding islands by pan 

 ice, and pushed along the bottom of the sea into these profound sub- 

 marine valleys during a period of general submergence, will be pro- 

 tected from the action of the waves, and the loose blocks and boulders 

 will have a forced arrangement in the mud, as if they had been 

 pushed over a bank, and thus produce the irregular disposition so 

 frequently seen in boulder clay deposits. In such narrow and pro- 

 found valleys as those instanced, the accumulation of boulder drift 

 probably goes on at the present time, and may continue during a 

 period of elevation, until large portions of the drift are raised above 

 the sea-level and beyond the influence of the waves, which will attack 

 only its sea front. But the agent which gives rise to this hetero- 

 geneous mass is pan ice, and the formation of boulder clay is very 

 probably a part of its work over a vast area on the Labrador coast at 

 the present day, throughout the labyrinth of islands which fringe that 

 coast to a depth of 20 miles seawards. If one examines the local 

 deposits of boulder clay in various parts of Nova Scotia, with ice- 

 worn gneissic rocks close at hand, or underlying the clays, the con- 

 clusion that pan ice has been instrumental in accumulating many of 

 those deposits is irresistible." 



Post-pliocene of Prince Edward Island. — On this I had little 

 information in 1868, but have since studied it in some detail. 



The Triassic and Upper Carboniferous rocks of this island consist 

 almost entirely of red sandstones, and the country is low and undu- 

 lating, its highest eminences not exceeding 400 feet. The prevalent 

 Post-pliocene deposit is a boulder clay, or in some places boulder 

 loam, composed of red sand and clay derived from the waste of the 

 red sandstones. This is filled with boulders of red sandstone derived 

 from the harder beds. They are more or less rounded, often glaciated, 

 with strise in the direction of their longer axis, and sometimes 

 polished in a remarkable manner, when the softness and coarse 

 character of the rock are considered. This polishing must have 

 been effected by rubbing with the sand and loam in which they are 



