INEQUALITIES OF SEDIMENTATION 345 



open sea to raise the general temperature while on the Elsemere side the 

 Arctic current with its continuous stream of ice blocks the bays and does not 

 allow the open water to ameliorate the cold of the ice covered lands. 



It is evident that currents trending in opposite directions on 

 opposite sides of narrow sea ways will tend to develop marked 

 contrasts in the kind as well as in the amount of sediments which 

 they distribute in comparatively limited areas. 



In Chesapeake bay'HiInter has shown that both erosion and 

 accretion are contemporaneously in progress in adjacent parts of 

 the bay. He finds that in the area studied, "The areas subjected 

 to erosion aggregate 35 square miles and those subjected to sedi- 

 mentation 9 square miles, making an excess of 26 square miles 

 .eroded."^ 



In the Bay of Fundy the processes of deposition and scour are 

 both active as Matthew^ has pointed out. His statement is sum- 

 marized as follows: 



In the Bay of Fundy the velocity of the tide varies from two to three knots 

 at its mouth to seven or eight knots in the Parrsboro passage near its head. 

 Near its mouth, on the New Brunswick side, a portion of the bay is separated 



by a chain of islands, and is called Passamaquoddy Bay The rush of 



the tide through these passes causes a roaring sound which may be heard for 

 many miles, and the whirlpools in them are strong enough to upset boats and 

 careen large vessels; both channels are full of deep holes, ledges, and pointed 

 rocks. At Quoddy River the tide passes over barriers having only fifteen 

 fathoms of water at low tide, yet within owing to the erosion of the tidal 

 currents, there is fifty fathoms in the narrowest and straightest part, and thirty 

 fathoms where it merges into the shallower water of Passamaquoddy Bay. 

 .... Up in Chignecto Passage also off Cape Enrage, there is a trough scooped, 

 out by the tide, which is outlined by the thirty, twenty-five, and twenty-fathom 



contour lines But it is in the eastern arm of the Bay of Fundy — Minas 



Channel and Basin — that the scouring action of the tide is most conspicuous. 

 .... The violence of the current in the deep troughs of Minas Channel and 

 Basin occasions the roughest bottom observable anywhere in the bay, for at 

 these points rock and gravel compose the bottom over which the tidal waters 



run The north side of the Bay of Fundy having the slower run of tide, . 



and being that along which the principal rivers enter, has in parts a muddy 



'J. F. Hunter, "Erosion and Sedimentation in Chesapeake Bay around the 

 Mouth of Choptank River," U . S. Geol. Siirv. Prof. Paper goB (1914), p. 14. 



^ G. F. Mathew, "Report on the Superficial Geology of Southern New Brunswick," 

 Can. Geol. Siirv. Rept. of Prog, for iSjj-jS (1879), PP- 18EE-22EE. 



