The Geology and Physiography of the ^\\)ngong-Cardlp Area. 269 
The southern extension of this structure is unknown, although it is 
signiticant that four miles south, on the noi’th bank of the Cardup Brook 
the gneiss foliation strikes north-north-east and dips \vest. 
South of Wongong- Brook there is considerable reversal of dip on the 
Avest limb of the syncline. Tlu'se west(‘r]y dips may be due to either to 
dragfolding (as illustrated in Plate 2, Section A-B) or to intrusions of aplo- 
granito. The interpretation of this structure as a syncline is confirmed in 
the distribution of the quartz veins. The X.W. trending veins are tin* best 
develojied in the area and are most abunrlant in the vicinity of the Be(*nyup 
Brook at the crest of the anticlinal structure. The absence of such large 
quartz veins in the Wongong valley may be exi)lained by the general synclinal 
structure of that pari of the area.. 
The “blows” outci'op “<*n echelon” and do not pass through the contact 
of the granite gneiss ami tin* Cardup series. A similar relationship has been 
observed in the (piartz bloAvs at Armadale { Prider, 1941), The small north- 
south blow Avhich disappears under the laterite south of Beenyup Brook 
represents the north-south type which occurs at Armadale. Weathered 
sericitic bands in the outcro]i suggest replacement by quai'tz in a zone of 
sheared granite and gneiss. 
B. Cardup Series. 
The contact of the series with the granite gneiss is nowhere exposed, 
but it can be fixed within half a chain in many i)laces by means of slate 
fragments in the soil and outcrops of the basal sandy beds. Outcrops of 
these sediments are found along the foot of the scarp, exc('|)t between the 
BrickAvorks Quarry and the Kitle l?ang(‘, AA'here laterite ])ebbles and sand 
obscure the geology. From north oi’ the Wongong Brook to the xArmadale 
area the series is either abs('nt or comi)letely obst-ured. To the south it 
appears to persist at least as far as Wuiidijong (IJonman, B)12, p. 63). 
The strike of tin* contact is dob® Avhich conforms with the obseiwed 
strikes of the sei’ies near the contact, Avhere the average dip is 50° to 60° 
to the Avest. Small outcrops of epidotic (juartzite occur at Avide intervals 
along the contact, these outcrops are resistant to Aveathering and dip steeply 
Avest. 
At the State BrickAvorks Quan’y the (‘xiiosed series has the same 
succession as at Armadale, thus : — 
Upper (4) Epidiorite (?) — A sill-like body of red AA'cathered rock. 
(3) Banded White Slate. 
( 2 ) Black Carhonaceoiis Slate — Exhibits features indicating 
upthrust of (he series from the Avest (Prider, 1941). 
These are ; dragfolds pitching north at 45° : small reverse 
faults dip]>ing steeply Avest. 
LoAAT'r (1) Grits and Sandstone — In bands up to 18 imdies thick (some 
are baritic) Avhich allernat(* Avith Sandp Shale over 
several chains. Graded b('dding in the sandy bands 
indicates that the b(*ds are normal and not over-turned. 
Th(*se b(*ds lie uuconformnbly on the hybri<l gneiss. 
South of Beenyuj) Brook the Cardu]) seiies is exposed over a AAuder area. 
On the Cardup Brook, Avhite slate outcro])s half a mile AA’est of the granite 
gneiss-Cardup series contact. 
