452 THE CANADIAN NATURALIST. [Vol. vii. 



intercepts the tide. Surmounting this reef, the current again 

 plunges down into a trench 50 fathoms deep, and rushes along 

 through the Parrsboro Passage at the great velocity of 7 or 8 

 knots where the water is deepest ; but slackening to 5 or 6 knots, 

 where, in the more open part of the passage, the soundings rise 

 to 30 fathoms. Here the contour .lines, those of 30, 25 and 20 

 fathoms, take a bilobate outline, corresponding to the two arms 

 of Minas Basin ; and at 10 fathoms' depth, this line is tri- 

 lobed, showing the erosive influence of the tide even in the 

 middle of the basin : these three indentations answer to the Corn- 

 wallis, Avon, and Shubenacadie llivers, as will be seen if the 

 shallower contour lines be traced. A similar result of tidal 

 erosion may be detected in Passamaquoddy Bay, wheTe two 

 tongues of deep water reach up from the basin in front of La 

 Tete passage, on the contour line of 10 fathoms, to Hardwood 

 and Hospital Islands. 



Conclusions. 



Before summing up the results thus far obtained, through 

 observations made on the surface deposits of New Brunswick, it 

 may not be out of place to call attention to the wide difference 

 in composition, etc., between the beds, to the description of 

 which this article has been chiefly given, and the Boulder clay. 



The latter exhibits no such indications of the powerful and 

 destructive action of ocean currents, as are everywhere im- 

 pressed on the Syrtensian beds. It does not lie in stratified 

 beds, like the latter, nor is the clay sorted out, but it still 

 remains evenly distributed through the mass, in company with 

 fragments of stone that show no marks of free attrition against 

 each other. It could not have been exposed to atmospheric action 

 during its accumulation, for, as Dr. Dawson has remarked of 

 this deposit in the St. Lawrence valley, and as may also be seen 

 here, pyritous minerals in the stones of the Drift clay are quite 

 unoxidized, and the stones themselves show no evidence of aerial 

 wear. These considerations preclude us from regarding it on 

 the one hand as a deposit made in places open to the force and 

 sifting action of sea water in rapid motion ; and on the other, 

 they are not favorable to the view that these clays were left 

 exposed, on the surface of the continent, to the winds and rains, 

 by the retreat of the glaciers. There remains, however, one 

 explanation of their origin which, it seems to me, meets satis- 

 fttctorily the conditions of this deposit, viz., that it was pushed 



