The (iEOLouv and PHVsrooKAPHY OF THE Wonoono-C'ahdx’P Area. 281 
(2) Quartz x’cins aio tlev’eloped in all three areas, tlie trend being 
N.N.W. at Car<lu|), .X.\\ . at Armadale, and N.K. at Gosnells. In none of 
the. areas have (]uartz veins been observed to pass from the granitie roeks into 
the Cardup Scndes (although many wore traced to the boundary l)elween thes(‘ 
t \\ 0 formations) and this is the main o^'ide^ee for regai'ding’ the gi’anitie 
gneiss e(un|dex as pre-Cardup in age. (Juartz veins occur in the slates at 
Cardup l)ut those ai'o of a different type and proltably gtmetically related 
to the younger basic intrusives. 
(d) Basic <lykes an^ common to all three areas but a marked variation in 
trend is noticeable. In the Wongong-Cardup area and at Arnunlale the 
general trend is B.AV. with a few N.-8. dykes whereas at Cosnells the 
general ti’end is in a X.-S. direction. The basic intrusions are all of post- 
Cardu]) age. 
The Cardup Series is develoi>ed in all thr(‘(‘ areas and ihe succession, 
lithology, grade of metamorixhism and relation of the Series to the granitic 
rocks and to the lat('r basic intrusives are similar throughout . 
Post-(’ardup basic intrusives belong to two main types, (i) albite 
epidiorite and (ii) iiralitised (juartz dolerites, both of which are developed 
in all three areas. They haA'e been assigrual to two ages — the earlier albite 
epidiorites having accommodated thoraselves to the earth movements affecting 
the Cardu}» Series, while the later (piartz dolerites have been comparatively 
little altered. 
Although the .signihcance of the various structural [>atterns of these three 
areas (as seen in the general trend of the gneissic struclui’es, (piartz veins 
and basic, dykes) is not as yet completely understood, it is the authors* opinion 
that the Barling Range complex consists of an older hybridised granitic gneiss 
intruded by a later batholithie granite extending over the area behveen 
Gosnells (on the south) and Lower Cluttering (on the north). Offshoots 
(aplogi-anite) from this granite mass have penetrated the older hybridised 
gneisses lying to the south of Gosnells. The Cardup sedimentary Series is 
definitely of later age than the granitic rocks and the various basic intrusions 
are younger still. 
VI. GEOLOGICAL HISTORY OF THE AREA. 
(1) Period of granitisation, during whieh the hybrid gneisses were 
formed from older basic rocks. 
(2) Folding of the hybrid gneiss (by pressures directed from the 
N.N.W. and S.S.F.), probably closely followed by, or contemporaneous 
with, (3). 
(3) Aplogranite intrusions. 
(4) Earth movements, forming shear zones and joints in the gneiss, 
lollowed by the formation of quartz veins, whieh may represent the end- 
phase of the aplogranite magma. 
(5) Erosion of the granite and gneiss and deposition of the Cardup 
Series. 
(6) DoAvnwarp to the west of the area, causing upthrust of the 
Cardup Series toxvards the east over the granite gneiss. 
(7) Intrusion of the epidiorites. 
j 3.30/42 
