(’LAKKK AM) WlUJAMS. — (imlot/jf of Dorllllf/ ItUUfJC. 
170 
'V\[v uiisIk'mjamI granite of this locality is massive. The massive 
granite is continuous as far s(mth as the Koleystone Area. l'\avthor 
south, at Armadale, similar (juartz reefs have been noted in ^neissic 
.granite' aliont a hundred yards <‘ast of (’oombs’ (Quarry. 
ddie formation of tlii'se Ixdts of sliearinc;’ ami siliciticat ion is 
(>r latin- date than the intnision of l)asic dykes, across wliich, with 
1 he possibb* exceptions noted mule r ‘ ‘ basic rocks, ’ ’ shearing- persists. 
The basic dvkes themselves are intrusive into the i»ranite and its 
associat('d acid ami ultra-aci<i dm-ivatives. It seems most probable 
therefoiA* that these* (piartz rc'i'fs \v(*re formed later on, an<l are 
<piit(' distinct from, tin* (piartz veins previously rcT'ei-red to as rep- 
re*seii 1 ino- nltra-acid residual li<pio)-s from the ovanite magma 
sepieezed into the consolidating granite. 
E. Later Rocks. 
1. Lahrilc— Only in a t\*w plan's do the Darlington ;iml 
Ibdi'ystone Areas rise* to the* ‘ ‘ Late'iiti' Level’’ which in this region 
lies lu'tweeii (iOO and 701) fee't abo\e sea le\'el. The laterite of 
the Darling Itanges has lu'en (U'scriln'd and discussed elsewhere 
(Sim|)son 1012, VVoolnongh 1018, (’larke 1010) and w<‘ liave nothing 
of int(‘i‘est to add. 
2. .Wiini(m.---'V\\'o types of alluvium oe'ciir in the Darlington 
Ai'ea, that fonning the Oats in the lower part of the Helena, and 
high lev('l alluvium in tlu* former course of Smith’s Mill Brook. 
The first doi's not call for comment, tin' second is described in 
the I Miysiogra j)hy section. 
;!. Tallis hanks. — Tin* tributaidi*s of the Helena generally flow 
ill narniw \'-sliaped valleys. In many of these, running }>arallel 
to tin* wat(‘rcoursi‘, and at lu'ights varying from three to fifty 
fe(*t above it, is a st(M*p sided bank 1 to d feet higli of angular 
rock fragments, the stei'p side facing the stream. Similar features 
wei'(‘ noted in the Holeystom* Area. Tlu' origin of these banks 
is pu//liiig, ddiey look at first sight as if of human origin — made 
in clearing a track — but the places in which they occur make 
that theory unti'iiable. Possibly .lutson’s (‘xplanation (1921) — 
differc'iit ial erosion— -of the |)aralh‘l lines of rock debris on Lake 
Goongarrie which of course occui- undi'r \U‘ry different climatic 
and to|)ographic conditions is a])plicabh‘ to these banks, In the 
Darling Hangi's the unetjual I'rosion is due to the varying resistance 
to weatlu'iing of granite and ejiidiorite, at Lake (loongarrie wind- 
erosion of soft slinles unprot<‘cted by (piartz rubbh* is tlu* agent. 
