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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 9, 



In the Pays Plat, my notes seldom speak of foreign erratics. Most 

 of the loose rocks are from localities in a N.E. direction near at hand, 

 or not more than fifty miles from home. They are peculiar and 

 easily recognised ; consisting of various porphyries, pudding-stone 

 with nodules of primitive rocks, dense porcelain-like sandstone, and 

 Silurian limestone (both associated with amygdaloid). 



The Pays Plat contains several bare flat terraces, a mile or more 

 in diameter, with some very distant erratics and drifted trees scattered 

 upon them. 



Where the sub-rock is a dark amygdaloid, the beaches are rusty 

 black, with a few stray blocks upon them ; where it consists of por- 

 phyry or sandstone, we have a brighter or darker red, — the line of 

 division being abrupt and striking, far more so than would be, if there 

 were tides or currents in this lake. The large debris at the water's 

 edge of the mainland opposite the Slate Islands, near the Black River, 

 for some miles east and west, is composed of traps, red granite, sye- 

 nite, and quartz-rock, with finely granular limestone, very siliceous, 

 white, and fossiliferous. If this limestone be not from the north, 

 where there is plenty, it may form reefs in the depths of the lake. 

 The beaches of the syenitic district north of Peek River are largely 

 strewn with blocks of hypersthene, from the vicinity. 



For fifteen or twenty miles on each side of the Otter's Head (a 

 well-marked spot), by far the largest part of the detritus on or near 

 the beach is native, — if we except the limestone above referred to. 

 It is almost wholly derived from the imperfect grey granite and the 

 numerous trap-dykes of this vicinity. 



From Otter's Head along and across the great Bay of Michipicoton 

 to Capes Maurepas, Choyye, and Gargantua, the shores are com- 

 monly, but not always, too steep to allow of resting-places for wan- 

 dering rock-masses. 



Such as I noticed had not travelled far. South of Gargantua 

 Point, an amygdaloidal district, we fall in with the various coloured 

 sandstones of the region in some profusion, with a few amygdaloids, 

 traps, &c, as before. 



One mile S.E. of Gravel River Handed and found the larger debris 

 to be principally gneiss and greenstone, veined with granite or felspar 

 (found in the vicinity), — the amygdaloids and porphyries having dis- 

 appeared, the latter indeed for the last 100 or more miles. 



In the great bay of Huggewong, the loose masses on the beach are 

 principally the native white, slightly laminated, granite. 



In this neighbourhood I met with a singular freak of nature ; viz. 

 a handsome fir-tree growing on the flat upper surface of a very large 

 block of conglomerate (from Marmoaze on the north), itself standing 

 upon four boulders of granite. 



The bay next to Batchewine is lined with debris of white hori- 

 zontal sandstone (Potsdam) ; its ledges forming the projecting points 

 of the indents. 



Batchewine and Goulais Bays being close to the throat or narrows 

 leading to the river St. Mary, a considerable change takes place in 

 the detritus on their beaches ; which are plentifully strewn with large 



