114 



mated thickness, 70 to 80 feet. The general dip of the strata 

 seems to increase rapidly to the south, for in a gully trending 

 east and west through Section 4166 — wherein the eastern 

 quartzite band is exposed in a contorted state — the dip of the 

 clay slate, about 70 yards east of where the quartzite finally 

 plunges beneath the slate, is 40° east. As represented by 

 pi. vi., fig. 1., the rocks here have been powerfully affected by 

 an east and west pressure, and had the quartzites chanced 

 to have been less exposed a casual observer might readily 

 have been led to conclude that the distance represented 

 by the diagram contained at least five quartzite bands, 

 whereas there cannot be more than two. Likewise it will 

 be noticed that if denudation had extended a few more feet 

 in depth the contorted quartzites would have been entirely 

 swept away. South from this point the old rocks extend to the 

 west, and include three additional quartzite bands, which in 

 places — notably so in Sections 3271, 3272, and 3273 — have 

 undergone a considerable amount of east and west pressure, 

 the effect of which has produced a bold surface outline toward 

 the Little Para. 



A peculiar quartz reef, or dike, first begins to attract 

 attention from the debris scattered over the surface on the 

 western side of the eastern band of this series in Section 3091. 

 At the southern boundary of Section 3094, it is fully dis- 

 played at the surface ; and in a gully in Section 3268, it has 

 attained great proportions, and is somewhat columnar in struc- 

 ture. Its strike at this place is about north-west by west, its 

 dip from 70° to 80° south-west. Beyond this point it is not 

 seen, but about one hundred yards west by south, in Section 

 3270, a detached portion of the same material, some thousands 

 of tons in weight, is exhibited in regular order poised on a sub- 

 stratum of clay-slate. 



"Williams' quarries, in Section 3092, are opened in the 

 western bands of this series. A splitting up, or repetition, of 

 one or more of the bands appears to have been effected here, for 

 in the gully where the quarries are situate four bands of 

 quartzite are seen intercalated with the clay-slate in the 

 distance of little over 400 yards. 



In the bed of the Little Para Eiver, on the eastern side of 

 Section 4,400, a quartzite band is there seen in horizontal 

 stratification, which phenomenon, in connection with that at 

 Williams' quarries and several others of a similar kind through- 

 out the district, leads me to infer that the various bands (some 

 at least) as exposed at different inclinations in the bed of the 

 river and elsewbere, are repetitions at the surface of the same 

 beds. 



Returning to the north of the cross section. The quartzites 



