18T3.] 



[Lesley. 



L As to their situation. This belt of deposit runs along at the foot of 

 the mountain slope, rising upon it in one direction (south) and sinking in 

 the other direction (north) beneath the Yellow Breeches Creek and the 

 limestone eountry north of it- But although there is a continuous belt 

 of ore, the thickness of the deposit varies from mile to mile ; as also does 

 its width upon the surface. 



Formerly the slates which held the iron which mouldered into ore, 

 rode up on the side of the mountain in a continuous sheet, resting on the 

 great Potsdam Sandstone rock which is seen still resting upon the moun- 

 tain in places forming peaks and plateaux upon its side and summit. But 



FIG 3. 



great erosion has taken place, and in this erosion the slates have suffered 

 most, because of their soft, clayey nature, and because they contained a 

 large percentage of soluble limestone with the oxidizable iron. The 

 above diagram will show how this has been accomplished : See Fig. 2. 



As the erosion went on, the oxidized iron slipped with the heavy clays 

 slowly downwards, the whole mass pressing upon itself and crimpling as 

 it slid. The corrugations thus produced are visible in all the ore-banks. 



Some of the strata in the slate formation were more clayey ; others 

 mere sandy. Some held more iron ; others less. Hence we see great 

 masses of white clay parting the masses of ore in all the banks. We see 

 in one part of a bank wash ore ; in other parts solid ore. Hence also we 

 find in one place ore made cold-short by an overplus of silica (?) ; in 

 another place a red-short ore due to an overplus of lime holding sulphur- 

 ous traces ; in others a surplus of manganese ; in others again the ore is 

 is neutral. All these variations are due to differences of original compo- 



