and Geology of Lake Ontario. 267 



in hornblende, and near the cascade is quite the same as the 

 sienite of Markfield Knoll, in Leicestershire. 



On the north shore of the outlet, about three miles north- 

 east from Kingston*, and not far south from the sienite, the 

 ridges are of highly crystalline milky quartz, with a strong 

 tinge of blue, and spotted with iron rust. Whether these 

 strata be interposed, or result from a gradual change, I had 

 no means of learning. From observing a conglomerate, whose 

 nodules are of this rock, in many parts of this neighbourhood, 

 and from its fragments being frequent south-west even as far 

 as Lake Erie, I believe the milky quartz to be in great quantity. 

 At the " Marble Falls," on the River Gananoque, four miles 

 and a half from the St. Lawrence, there are ridges which are a 

 mixture of noble serpentine and white marble. The former is 

 pale and dark green ; its lusti'e and translucency (at the edges) 

 considerable : it is disseminated through the marble in shape- 

 less lumps of every size, sometimes few in number, and at others 

 constituting the greater part of the mass : or again, it is inti- 

 mately blended with it in clouds and convolutions. It is in 

 thick blocks. I have not seen it m situ. It occurs also near 

 Gananoque Lake. Twenty miles east of Gananoque village, 

 on the high road to Montreal, two or three miles north of the 

 St. Lawrence, the mica is in small brownish yellow scales ; so 

 abundant, and the rock so slaty, that it becomes a mica-slate, 

 with a vertical dip and S.W. direction. 



Thirteen miles west of Brockville, on the same road, we pass 

 for three miles through a district of white translucent quartz 

 in mounds, steep, shapeless, often ruinous, but still often be- 

 traying in its rents a south-west direction. It is fine granular, 

 passing into crystalline. One of these eminences, thirty or 

 forty feet high, half a mile north from the road, and near the 

 easternmost of two creeks occurring here, has a vein of iron 

 pyrites under the following circumstances. It is at the bottom 

 of a rounded cavity twelve feet deep and as many long, but not 

 quite so broad ; its sides consisting of very shattered quartz, 

 spotted with brown oxide of iron, and covered profusely with 

 an efflorescence, yellow and white, of sulphate of alumina. 

 The lower parts are studded with small masses of iron pyrites. 

 The vein itself is one foot and a half thick, and disseminates 

 itself into the surrounding rock. It is visible for one yard and 

 a half. It was discovered seventeen years since by a man 

 who was seeking his cow in the woods. He was within a short 

 distance of the spot, and on a sudden was startled by a tre- 

 mendous explosion, attended by volumes of smoke and sul- 



• On the farms of Messrs. Law (late naval storekeepers) and Mr. M'Kenzie, 

 (coiiiniander of the steamboat Frontcnac.) 



2 M 2 phurous 



