14 
Keith R. Miles. 
Accessory minerals in*esent are : — 
Rutile in very abundant scattered clusters and separate individuals 
of tiny o'olden yellow j risinatic crystals frequently occurring in 
geniculated twins, often as poikilohlastic inclusions in kyanite, but 
also scattered irn'gularly Ihrougbout the iiuartzite matrix. 
Sericite or muscovite occurs in some tiny parallel oriented rods 
“flowing-’ tliroiighout th(' (piart/ite matrix and also as a few larger 
flakes and string(*rs occasionally moulde<l upon or enclosed by kyanite. 
Zircon exists in a few rouiuh'd, colourless, zoned detrital grains 
often enclosed in kyanite. 
Hematite is ju'esent in a few small scattered grains, usually show- 
ing some alteration to limonite, while limonite occui’s as a thin 
secondary stain in a few j)laces, marking- the presence oi‘ small 
fractures upon the surface of the rock. 
Thus this rock is a kyanite-(|uartz schist. 
Tlu‘ simple mineralogif-al composition of this I'ock indicates a c(nnj)ara- 
tively simple clnmiical com])osition. From its mineral content it would 
ai)pear (o consist chiefly of silica, Hit)., and alumina, Ak.O,, with minor 
<juantiti(‘s of titanium oxide, TiO^. A remarkable featui’e of this rock is the 
almost comph'te absence of Fe in any form, particularly as from the field 
occurrenc(‘ it a])pears to gi-ade into normal bamh'd IVrruginous (piartzite 
along the strike. 
No chemical analysis of this rock has yet been made but as will be seen 
in the following section its remarkably close similarity to the Mt. L(‘onora 
rock indicates an essentially similar chemical comi)ositioii, and an analysis of 
the Camel Humps rock Avould ]>robably be found to compare \'ery closely 
with those of the Mt. Leonora type quoted below. 
MT. LEONORA, MT. MARCxARET GOLDFIELD. 
Field occurrence. 
Mt. Leonora lies about 3 miles to the south-southeast of the townsite 
oi Leonora and forms tlu' highest and most conspicuous summit of a long 
line of inl(H’mittent ridg(‘s and low hills which run northwards for many 
miles. 1 hose also extend southwaixls from the Trig. Station for about three 
miles in a line of I’ock outcrops which form ridges of g'ratlually decreasing 
stature ami which tinally disapix'ar beiuMth the alluvial flats of Lake Raeside. 
The rocks of which Mt. Leonora is composed are creamy yellow to light 
grey in (-olour and are usually dense, hard (piart/ose scliists of variable grain 
size, frequently having a knotted chai-acter. 
These rocks are distinctly Ixalded and dip fairly constantly at 00 ° to 
the west (S(v Fig. 4.). Tlnw were tlrst described’ in 1904 by C. F. Y. 
Jackson (15) who considered Mt. Leonora to be an area of “crushed 
granite,” despite the evidence of a chemical analysis of this rock (5084) 
published along with his descrij^tion. 
In 1909 A. (i. Maitland, as a result of a brief re-investigation of the 
field occurrence of the Mt. Leonora rock, pointed out its obviously bedded 
nature and from the Held evidence concluded it to be of sedimentary origin 
and not a metamorphosed granite (16). He also remarked that the quartz 
schists of the Mt. Leonora type extended noifhwards for over six miles Avith- 
out interruption to Mt. George. 
