Keith H. Miles. 
pressim*. It is ^'oneoi^■ablo that in the Camel Humps area tlu'se eonditions 
Avere produced as a largu scale granite cotitaet-inti’usion effect i)ut it ai)pears 
improhahle that dmmig such an intrusion shearing stress would remain suffi- 
ciently eotistanl for the foimiation of kyanite as the sole representative of 
the aluminium silicate minerals. There is no evidence of the existeiici* of 
andaiusite at any stage in the develo])nient of the Canu‘1 Humps rock. In 
the held the lU'arest undouhted outcrops of intrusive granite are about a mile' 
to the west of the outcrops of kyanite Cjuartz schist. Th(‘ actual contact is 
marked by a thick layer of overburden which co\a*rs the interAuuung country. 
The only other iiiti’usive rock in tlu‘ vicinity is a \ery small dyke of acid 
]>orphyrv occurring near the southei'n Camel Hum]). * k>ntact thermal (d’fects 
of this intrusion can ho assumed negligible. 
No large body of undoubted intrusiAT gi-anite or other igneous rock 
is knoAvn to (vvist in the immediate vicinity ol‘ IMt. la'ouora. The general 
north-south sehistosity of the country in the neighbourhood of both the 
Camel HiimjAs and Leonora Avas pi-obahly the r('sull of regional shearing 
pressures mostly contemi)oraneous with the formation of the nudamoridiic 
minerals. 
It i^- e\-ident that the I\lt. Leonora ro('k eommenc(’d re<M'ystallisation 
largely under deficient shearing sti’ess as shoM'u by' the piedominaut (^arly 
development of the andaiusite. At a slightly latei' stage, however, wliilst 
the rock Avas still at a fairly high t(*mi>eratiir(‘, it luH-aine sidijectful to in- 
ci'easing sheaiing stu'sses — i>robably as'^ociated with folding movements re- 
si>onsibl(‘ for the sehistosity' oi' adjaetnit grccmstoiic. 'fhis ])r('ssar(* iinally 
reached siudi a stage* tlnd further growlh of the so (-allerl “anti-stress’^ mineraL 
andaiusite was completely' inhibited and it commenced recrystallisation into 
the* more sta})h* kyanite* and sillimaiute. 
Ace'ording to Harke*!’ (4, p. 'id'J-b) this association of andaiusite Avitli 
kyantte is dee*id(*dly' rare. He (piotes an occurrenn-e* in the* Fliiola district, 
near Davos (Switzerland), Imt here it is be*lien'eMl that tin* formation of the 
andaiusite' helonm'd to a late*]' { base ol‘ me't:imor]diism afteu' a ra]nd falling'- 
otf ol' shearing sti'ess while tein])e'ratures still I'emained high, l-lxamph's of the 
growtii of kyanite' in psenelonior[)hs afte'r chiastolite* as a re'sidt of legional 
metamoi'piiisiu su|ierim])os(‘el e)n normal theumial medamorphism of an are-a of 
original politic sediments are recorded by C. K. Tilley from Koss-shire-, Scot- 
land (1). 
The* pi'e'smu'e* of such a high graele inedameirphie' minei'al as kyanite in. 
rocks helie'ved to form ]mrt e)f the Older Gi’eamstone Se'vies is of partiemlar 
interest in set fai* as it shov\s that in some portions of the Ht. Mai'gai'(*t Cold- 
held this Serie's lias suffered a higher grade of melarnorpliisiii than had 
in-eviously licen recognised ihe're*. In these leAcalities tlu' rocks ha\'i* c\’idcntly' 
been suhjecte'd to regional ]n’essnre‘S and temperatures comiiaiable with tho^e* 
Avhicli must have existed in some of the moi'e advanced metamorphic areas 
of the State, e.g.. the Cluttering Valley ami tlu* Clackline- York districts. 
Igneous greenstones, helievial to ln*ne Ikm*!! chiclly hi\as (■ontemporaueous 
with the sediments, iirobahiy form the Inilk of the Older Oreenstone Series 
in most parts of the Mt. Margaret Ooldhehl. In some places well preserved 
striu'tural foatnn*s indicate that thest* igneous giaH*nst)UU‘s ha\'(‘ suffered \ery' 
little metamorphism of any kind but in the localities described above the 
])reseneo of kyanite in associated mota-sedimentary beds sIioav that here at 
least they havt* been subject^al to high stri'sses and t(*mp(‘ratures. IIoAveveiv 
their composition is such that they shoAV no striking e\id(*nce of th(*se high 
