The CJ-bology and Physiography of the Gosnells Area. 249 
(jUfirtz vein, nearly 100 feet wide, forms the crest of the steep northern slope 
of stream A and crops out over a distance of about half a mile on a course 
just north of east. 
A lar^e family of veins makes up the quartz “blow.’’ It may be traced for 
1% miles till it is lost under the laterite cover to the east. Small pebbles of 
milky, sub-ang-ular quartz in laterite nearly a mile farther east are probably 
derived from an extension of the “blow.” 
Near its southern end, the quartz body consists of four or five parallel 
veins (each about one chain wide), spread over a width of 20 chains. Be- 
tween these veins, the underlying rock is obscured by soil and by quartz 
talus. In (juarries and cliffs in the ^0>low,” however, schistose quartz sericite 
rock and thin quartz \^eins are exposed between the strongly outcropping 
veins. 
The “blow” runs slightly obliquely to the course of individual veins. 
The latter trend about 80° south of Ellis Brook, and between 50° and 90° 
farther north. Vertical major joints are common in quarries and cliffs, and 
strike 135° near the White Bock and Mountain Quarries and 65° north of 
Ellis Brook. Sericite schist and (iuartz are roughly banded near the :Moun- 
tain QuaiTy: the sti'ike and dip of these bands (strike 20°, dij) west at 00°) 
may i:)ossibly be the strike and dip of some of the veins. Tin* l)anding may 
be thought to be a relict sedimentary structure, and the quartz “blow” to be 
a huge xenolith of sedimentary rock in which (juartzose bands now appear 
as quartz veins. But there is w further sign of sedimentary structures even 
near the centre of the mass, and petrologically, both in hand s})ecimen and 
in thin section, the quartz of the “blow” resembles that of the smaller veins, 
and is thus igneous in origin. 
The acid igneous solutions from which the quartz veins are derived rose 
along planes of shearing and faulting in the granite. But, as the granite is 
structureless, there is no apparent explanation why these directions of weak- 
ness trend predominantly slightly east of north. 
Many of the <|uartz veins have been examined for gold. The large vein 
just north of stream A has received particular attention. Five costeens have 
been dug in it, and Messrs. Boss and Son, in 1909, put in an adit-crosscut 
1/5 feet long and a shaft 2/ feet deep. The State Mining Engineer, A, 
Montgomery, visited the prospecting allotment and reported (1910, p. 124) 
that “the reef is very poor indeed in gold and (juite un[)ayable at present.” 
The cross-cut was (‘xtended 40 feet, but mining Avas then abandoned and 
nothing has since b(‘en done. 
The (juartz of the “bloAv” Avas recently quarried as an aggregate for 
concrete and for bitumen roads, but owing, it is said, to the heavy AA’ear of 
the rock-crushing machines, it has not been Avorked since 1929. 
1). Cardup Senes. 
This series outcrojis west of the granite, near Ellis Brook. It strikes 
nearly due north, parallel to its contact Avith the granite and dii)s Avest at 
(usually) 50° to 55°. The dip steepens to vertical near the barite pits, but 
this is due to buckling ])y the nearby basic intrusion. Faint jointing-^ practi- 
cally normal to the strike, is deve1o})ed in the slate's, but no fracture cleavage 
or dragfolding Avas noted. 
