200 
xiv. Maitland, Yorke's Peninsula. No. 1 bore. 
Macroscopic characters —Hard, brownish- 
pink quartzite, very vitreous on fracture. Abundance of 
clear to cloudy pinkish felspar present, and some rock par- 
ticles. Some of the quartz is miiky to opalescent, but most is 
clear. 
Microscopic: charucter s.--Very similar to 
those of the Mitcham and Burnside rocks. Texture coarse. 
Quartz is most abundant mineral, but felspar is plentiful. & 
good many schist fragments are present. The chief feature 
about the rock is the extraordinary perfection of the secon- 
dary outgrowth of the quartz grains. All the quartz grains 
must originally have been perfectly rounded. Secondary ad- 
dition of quartz in optical continuity has produced a perfect 
mosaic. The original surfaces of the grains are indicated оу 
lines of dusty inclusions. (Plate xxxiii., figs. 2 апа 3.) The 
secondary silica is all quartz, no chalcedony having been pro. 
duced. 
xv. Two miles west of Ardrossan, Yorke's 
Peninsula. This rock ovtcrops on Mr. Dinham's farm, near 
the road to Maitland. It lies directly upon the upturned 
edges of pre-Cambriau schist and gneiss and is overlain, 
apparently unconformably, by very fine-grained vitreous 
quartzite and the strongly chalcedonized Turritella aldinge 
bed of the Eocene. 
Macroscopie characters.—Very variable in 
hardness, some of it being almost unconsolidated sand, while 
in the same hand specimen are portions with the characters 
оі an intensely hard quartzite. The material is almost en- 
tirely quartzose; a iittle chaleedony is present in the con- 
solidated portions. 
Microscopic | characters.—On casual exami- 
nation the large amount of milky white material in the rock 
suggests an important felspar content, but optical investiga- 
tion shows that all this material is quartz, rendered almost 
opaque by the enormous number of minute, irregular gas 
cavities it contains. An appearance simulating cleavage is 
due to the arrangement of inclusions along well-defined parat- 
lel planes. No composite particles were observed. The sec- 
ondary outgrowth of the originally rounded quartz fragments 
is very remarkable. ‘In some parts of the rock adjacent se. 
condary rims have met and mutually interfered, and a 
mosaic is produced. fn other portions the rejuvenescence has 
reproduced ideally perfect quartz crystals with their free ends 
pointing into a cavity now completely filled with chalcedony. 
A little rutile is present in sharp crystals, and some hair-like 
prisms which may be rutile. "There is a little muscovite an4 
zircon and some dark brown tourmaline in grains and prisms. 
(Plate xxxi, fig. 4.) 
