92 
E. DE C. Clarke, C. Teichekt and J. H. H. McWhae. 
of Priiiccf-:^ Royal, but there are rather extensive outcrops in a gully whieli 
runs north just west of the townsite and in low breakaways north-west of 
the townsite. 
Text tig. 4. 
Contact of Prc-Caniljrian and Tertiary roi-k? in a small gully about eight feet deep, 
40 c'liains Avest of Old yiain Khaft at Ibiiic'css Royal townsite. Weathered Pre- 
Cambrian rocks are exposed in the bottom of the gully, blue clay and white shale 
along the sides. The contact is marked l)y a black line. 
The sediments lie with marked unconformity on Pre-Chunbrian rockft 
Avdiich apfK'ar to 1)(‘ chielly amphihoIiU's with oc(‘asioiial iK)rp]iyry dykes and 
to belong to the Ivalgoorlie-Yilgam System. The surface of the Pre-Cam- 
briaii, at its contact with the spongolite series, is weathered and uneven and 
is overlain by two feet of blue clay: then come two to four feet of Avhite 
shale, followed by a bed of spongolite 20 to 25 feet thick which in some 
places is white and is composed very largely of sponge spicules: in others, 
where it is red, spicules are not nearly so abundant. These three beds are 
conformable. 
The sediments thicken as wo apiiroach L. Cowan because they occupy 
a north-south depression in the Pre-Cambrian rocks which deepens north- 
wai’ds. On the west, south, and east sides Pre-Cambrian rocks constitute 
