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201 
x. Doro: add Ivers: 48:«dtsh. ccock Ar reo ва! аыйл 
quarter of a mile north-east of Miss Norton's house. 
Macroscopic characters. —Rather coarse, 
greyish grit, with a notable amount of pinkish and whitisia 
felspar. Fracturcs around and not across the grains. 
Microscopic chearecters.—Textursis medium. 
Quartz is predominant, but felspar and chert fragments are 
notable in amount. Quartz is in angular fragments, almost 
all of which show strain structures. Slight trace of rejuven- 
escence of grains, and in at least one instance a reconstruct- 
ed granule has been subsequently broken (possibly owing to 
a second period of erosion and transport). The felspar is 
nearly all albite, there is very little orthoclase, and no micro- 
cline, the chert particies are reddish and nearly opaque. 
There is a good deal of yellowish opaque material, the de- 
composition product of rutile, and a few flakes of clastic 
mica. Cement is quite plentiful, and is mainly chalcedonie, 
though some calcite is also present. The latter may be allo- 
genic material (derived from the Cambrian limestones upon 
which the rock appears to rest). 
хуп. One and a half miles so ub son 
Ardrossan. Ialt a mile west of Parara. This rock 
occurs only about a quarter of a mile north of xvi., but, both 
in the field and under the microscope, it appears quite dis- 
tinct from it. Traced in a northerly direction its texture 
varies from an incoherent sand to an intensely hard and 
tough quartzite. 
Microscopic character s.—Moderately coarse, 
sub-angular grains of quartz, set in a fine-grained mosaic of 
the same mineral. All the grains are in optical contact. 
Many of them show traces of rejuvenescence, some of them 
to a high degree of perfection. Some brown tourmaline is 
present in small fragments. 
The stratigraphy of these three quartz rocks from Ardros- 
san is very complicated, and needs further investigation for 
its elucidation. 
xvii. Plain east of Mount Remarkable. 
Macroscopie characters.—Very hard rock of 
medium texture, composed mainly of colourless quartz, with a 
little whitish material. Very vitreous on fracture. 
Microscopic character 5.—Rock consists of 
medium-sized, rounded grains, set in very fine textured in- 
terstitial cement. The latter makes up about 25 per cent. of 
the whole rock. About 95 per cent. of the larger grains are 
clear quartz, the remainder are ferruginous mica slate, gene- 
rally excessively fine-grained. There is no felspar in the sec- 
tion. Rounding of grains is generally quite complete. In 
