GILPII? — CARBONIFEROUS DISTRICT OF ST. GEORGE's BAY. 361 



The prevailing indraft of westerly wind, and the contour of the 

 Bay causing a tide to flow in on one side and out on the other, 

 have deposited huge sand banks at the mouth of the Main River. 

 In many places these banks show beds of black sand, varying from 

 one to thirty inches ; doubtless research would expose thicker beds 

 in localities not now subjected to the action of water. 



The origin of these iron sand ores is to be found in the crystal- 

 line rocks, from the disintegration of which they have been derived. 

 The action of the waves, by virtue of the greater specific gravity of 

 these sands, efiects a process of concentration, so that considerable 

 layers of black sand are often found on shores exposed to wind and 

 tide. The composition of these black sands vary according to 

 locality, but as found on the St. Lawrence consists of magnetic 

 oxide of iron, with a large mixture of titanic iron ore, and more or 

 less of garnet. The purest specimens hold about forty-five per 

 cent, of black oxide. 



Indian Head is a mass of trap forming the south side of the 

 coal field of that name. A visit to the measures exposed on the 

 Indian Brook was impracticable, but on the authority of Prof. A. 

 Murray, Chief of the Geological Survey, undoubted coal measures 

 are found there. A small seam is known to crop near the shore, 

 but the coal is of very inferior quality, hard and full of stone. 



Five miles to the westward at the mouth of Kippens Brook, is 

 one of the most magnificent exposures of gypsum in the world. 

 The brook flowing obliquely across the crop of the bed, has bared a 

 great cliff', four hundred yards long and one hundred feet high, of 

 soft white gypsum of the finest quality. Parts of the cliff" contain 

 alabaster of unusual clearness. The specimens sent from this 

 locality to Boston and Philadelphia were much admired. 



Following the brook upwards, the measures which at the gyp- 

 sum pitch to the east, gradually bend round to the south, and we 

 find ourselves in the bed of a synclinal which has been frequently 

 shifted to and fro by upheavals. The measures consisting of sand- 

 stones and shales with beds of grit, rise towards the hills on each 

 side. After a few miles the measures become level and are con- 

 nected with those of Indian Brook. There is a large tract of level 

 land extending for several miles beyond this point, as yet unexplor- 



