20i NIAGARA FALLS. 



X.ETTER XLVll. 



Cataract of Niagara ^ September, 1820. 

 Mr Dear Sir, 



I BELIEVE that in a former letter I mentioned 

 the nature of the rocks wliich constitute the pre- 

 cipice of the Niagara Falls. The substratum is 

 a compact flesh red sand stone, infusible before 

 the blow pipe, but is rendered friable, and retains 

 its color. The upper strata are composed of 

 carbonate of lime, of im.mense volume and density. 

 This sand stone becomes brittle when exposed to 

 the atmosphere, and as it descends it increases in 

 fragility. About tvv'o miles north of the cataract, 

 ihere is a sulphur spring near the river, where the 

 sand stone is the lower stratum. At a considera- 

 ble distance down the DeviVs Hole, the same rock 

 appears, and also near the bottom of the great 

 ridge, or slope, at Lewiston. The country abovQ 

 the heights of Lewiston and Queenston is a vast 

 plain, from which there is an abrupt descent of 

 near three hundred feet, into another plain at 

 Lewiston, and in which plain is Lake Ontario. 

 The upper slope is table land, as well as the plain 

 below, and this produced the French denomina- 

 tions of Upper and Lower Canadgi. The river 



