WEST OF OAEBONATE FAULT. 439 



developments are not carried on regularly in any of these shafts, owing to 

 great influx of water and nothing definite can be said as to the extent or 

 conditions of the ore body in that direction.' 



Area west of Carbonate fault. — The Original rock surface of Carbonate Hill 

 west of the line of Carbonate fault slopes off very rapidly, as shown by the 

 sudden deepening of the Wash in the various sections. The line where the 

 slide of the steeper slopes gives way to actual Wash, or rounded bowlders 

 and gravel of rearranged moraine material, marks a sort of beach-line in 

 Glacial time, up to which the ice sheet must have extended in order to trans- 

 port the bowlders, some of which (at the mouth of the Crescent incline, for 

 instance) must have been brought from near the crest of the range. The depth 

 of this mass of detrital material probably reaches 150 to 200 feet along the 

 western edge of the map, and there is some evidence to show that the under- 

 lying Lake beds extend up to the base of the steeper rock-surface slope, as 

 shown in the sections. Under such a mass of clayey gravel, which, like a 

 sponge, permits the passage of water through it and yet keeps constantly 

 satui'ated, the rock surface disintegrates and its minei'al constituents are 

 decomposed more readily than elsewhere, and the porphyries especially 

 lose rapidly their distinctive characters. With these conditions of actual 

 surface and rock surface the determination of geological structure is 

 naturally difficult, and this difficulty is enhanced by the fact that, except 

 at the northern and southern ends of the area mapped in the lower Henriett- 

 Waterloo and ^tna-Pendery claims, respectively, the little underground 

 ex])loring that has been done was simply for prospecting purposes, irregular, 

 without system, and the workings are as a rule no longer accessible. The 

 structure of this i-egion, as represented on the sections, is the embodiment of 

 information obtained at the expense of infinitely more time and labor than 

 the examination of a large mine would have required, and yet is fixr from 

 satisfactory in its character. For this reason, while the structure of the 

 lower portion of the hill, as shown in Sections B, H, and I, may be taken as 



'Since the completion of field-work, at a depth of 633 feet contact has been reached in the Wolfe 

 Tone shaft, which is a short distance east of the Brookland. Ore and vein material are said to have been 

 about forty feet thick, the former occurring both as carbonate and as sulphuret. Below this a body of 

 porphyry was found, which from description is apparently Gray Porphyry and may be the eastern con- 

 tinuation of the main sheet which has been develojjed in the Lower Waterloo workings. 



