Xo. 1.] DAWSOX — POST-PLIOCENE. 29 



ther, it is the Boulder-clay connected witli this S. W. striation 

 that has hitherto proved most rich in marine shells. 



If, however, we pass from the St. Lawrence Valley up the 

 valleys which open into it from the North, as for example the 

 gorge of the Saguenay, the Murray Bay River, or the Ottawa 

 River, we at once find a striation nearly at right angles to the 

 former, or pointing to the South-east. 



At the mouth of the Saguenay, near Moulin Bode, are striae 

 and grooves on a magnificent scale, some of the latter being 

 ten feet wide and four feet deep, cut into hard gneiss. Their ■ 

 course is N. 10° W. to N. 20° W. magnetic, or N. 30° to 40° 

 W. when referred to the true meridian. In the same region,, 

 on hills 300 feet high, are roches moutonnees with their smoothest 

 faces pointing in the same direction, or to the North-west. This- 

 direction is that of the valley or gorge of the Saguenay, which 

 enters nearly at right angles the valley of the St. Lawrence. At 

 the month of the Saguenay the Lark Shoals constitute a mass of 

 debris and boulders, both inside and outside of which is very 

 deep water ; and many of the fragments of stone on these shoals 

 must have been carried down the Saguenay more than fifty miles. 



In like manner at Murray Bay there are striae on the Silurian 

 limestones near Point au Pique, which run about N. 45° W. but 

 these are crossed by another set having a course S. 30° W., so 

 that we have here two sets of markings, the one pointing upwards 

 along the deep valley of Murray Bay River to the Laurentide 

 Hills inland, the other following the general trend of the St. 

 Lawrence valley. The Boulder-clay which rests on these striated 

 surfiices is a dark-coloured Till, full of Laurentian boulders, and 

 holding Leda truncafa, and also Bryozoa clinging to some of 

 the boulders. In ascending the Murray Bay River, we find 

 these boulder-beds surmounted by very thick stratified clays, with 

 marine shells, which extend upward to an elevation of about 800 

 feet, when they give place to loose boulders and unstratificd drift. 

 About this elevation, the laminated clays meet a ridge of drift 

 like a moraine, crossing the valley, which forms the barrier of a 

 small lake, Petite Lac, and a second similar barrier separates this 

 from Grand Lac. If the valley of Murray Bay River was oc- 

 cupied with a glacier descending from the Laurentian hills inland, 

 which are' probably here 3000 to 4000 feet high, this glacier or 

 large detached masses pushed from its foot, must have at one 

 time extended quite to the border of the St. Lawrence, and at 



