The Blue Mound Qiiartzyte. — Hubbard. 165 
The quartzyte is much jointed and hence in weathering- 
breaks off, in consequence of which there are many large 
masses of the pink to reddish-brown coated rock strewn 
along the slope and even nearl}- to the base of the mound. 
The rocks thus detached gradually slip down the hill and 
disintegrate as they descend. Hence we find onh' small 
ones near the base. The quartzyte is destitute of bedding 
planes and stratification of any kind and does not lose its 
quartzitic appearance and smooth conchoidal fracture in 
weathering. Therefore pieces near the foot of the mound 
are very similar to those at the summit except they are 
much smaller. 
A few pieces of this la)er, but no continuous strata, oc- 
cur upon the little mound just to the east; and upon the 
west member of the Platte group there is perhaps ten feet 
of it in the highest parts. I have been unable to find this 
stratum or any reference to it at any other point. No hill 
reaches high enough into the geologic scale to attain to the 
horizon of the quartzyte. Whether it were ever continuous 
as were the other layers of the Niagara, over this region, 
probably will never be known, but its presence on the Platte 
mounds would argue for a somewhat extended area. 
Samples were taken from several places for chemical 
analysis. The composition and structure seems quite uni- 
form at all points observed. From five samples, three gave 
test for traces of carbon dioxide; two gave no trace. The 
rock is ver}' low in carbonates. Iron was found in all tests 
but is only a stain, occurring mostly along cleavage planes 
and fractures but in places colors the rock pink or tints it 
a reddish brown. It is in the form of the sesquihydroxide 
and amounts to little more than traces in the rock. No 
alumina was found. 
Upon fusion with alkaline carbonates the rock is com- 
pletely decomposed and from the analysis was found to 
contain over ninety-nine per cent of silica with traces of 
calcium and magnesium. This is all the anal\'sis )'ielded. 
To all appearances the rock is a pure quartzyte. Its hard- 
ness is about seven and its specific gravit)- is that of cjuartzyte. 
PVacture is deeply conchoidal. 
There are found in this stratum a number of fossils. A 
