and Geology of Lake Ontario. SiS 



the Genesee Falls much of it, however, is pale-brown, less 

 schistose, earthj', and interspersed with quartzose grains ; — a 

 kind of compound sandstone not to be distinguished in hand 

 specimens from real grauwacke slate in its finer varieties. 



Geodifcrous Rock, — a fetid, often very massive stratum of 

 limestone, usually very dark-coloured, but sometimes lightgray, 

 is only met with in the western half of Lake Ontario. It is 

 distinctly seen to rest upon, and moreover to pass into the last- 

 described rock, — a fact which Mr. Eaton has not mentioned. 

 At the Genesee River near Rochester, it is thirty feet thick, 

 at Lockport fifty, and at Niagara seventy. (G. S. p. 135.) 

 " Though this stratum is generally a very pure carbonate of 

 lime, mostly a dark-coloured formless rock, yet in many re- 

 spects it resembles the gray siliceous transition sandstone, which 

 I have described under ' calciferous sandstone.' " They both 

 contain geodes of quartz crystals, calcspar, and sulphate of 

 zinc. This contains sulphate of strontian; that sulphate of 

 barytes.— (G. S. p. 135.) 



In this Umestone Mr. Eaton finds " snowy gypsum, selenite, 

 dog-tooth spar, pearl spar, fluor spar, waxy zinc blende, sul- 

 phate of strontian, and quartz crystals." — (P. 134.) 



For further particulars respecting this rock, vide " Geo- 

 logy of the River Niagara," speedily to be published. 



The two rocks next succeeding in Mr. Eaton's series are 

 the " Cornitiferous " and " Pyritiferous Lime-rocks," of which 

 I shall here say very little ; as they belong to the River Nia- 

 gara and Lake Erie. The first is essentially the same as the 

 geodiferous, but is full of chert in nodules and layers. The 

 second is a siliceous or calcareous rock, with an aluminous 

 cement, and abounding in iron pyrites. Mr. Eaton considers 

 it to be the equivalent of the pyritous shale of Whitby and 

 Charmouth, a member of the lias formation. It is visible on 

 the south side of Lake Ontario, but at some distance from it, 

 fromOnondago salt-springs to Lake Erie, 150 miles. — (P.] 45.) 



The rocks of the north shore of this lake are by no means 

 so fully nor so frequently brought into view as those of the 

 south shore, which have now been described. 



I have no doubt that, as far as they go, they are parts of the 

 same series ; but excepting the two lowest, they occur in such 

 very small and distant patches, on the same level, and so much 

 weathered, that to assign their geological relations is a very ha- 

 zardous attempt. The salt formation certainly exists dirough- 

 out its whole extent; but though I have carefully examined 

 the greater part of the north shore (180 miles) in a boat, and 

 passed more than once at great leisure, by land, from King- 

 ston to York, visiting the middle parts of the rivers Trent 



N.S. Vol. 5. No. 29. Mai/ 1829. 2 Y and 



