251 



Kilometres gypsum and china clay may be seen in crumb- 

 ling outcrops of red, yellow and white. The 

 highly coloured decomposed material is almost 

 devoid of vegetation. 



The Cache Creek formation crosses the river 

 at Spatsum, and extends southward to Toketic, 

 where black argillites and quartzites of this 

 formation pass under the Spence's Bridge Vol- 

 canic group. 



Between Spatsum and Toketic there are two 

 places to be seen from the railroad where the 

 Jura-Trias rocks rest unconformably upon the 

 Cache Creek formation. The largest outlier is 

 on the west side of the river and forms a high 

 hill separating the Thompson from Venables 

 valley. Venables creek flows through the south- 

 ern end of the exposure, and has exposed a very 

 fossiliferous section near 89-Mile Stable on the 

 Cariboo road. 



The other outlier, which is in a badly 

 metamorphosed condition, outcrops high up on 

 the east side of the Thompson valley above 

 the great rock slide, at the base of which is 

 nestled an Indian village and church. The 

 Jura-Trias is here in contact with the grano- 

 dioritic batholith and basal Cache Creek rocks. 



There are a series of strike ridges and ravines 

 paralleling the cliff face 1,500 feet (457-2 m.) 

 above the railroad. The Jura-Trias metamor- 

 phics dip flatly to the west while the underlying 

 Cache Creek rocks, where observable, dip 

 steeply to the east. The Jura-Trias rocks are 

 crevassed along joint planes nearly at right 

 angles to their bedding. 



A couple of miles south of the Rock slide at 

 the mouth of Pukaist creek, the railroad cuts 

 transversely through Cache Creek marble, well 

 exposed across the river in the Canadian Nor- 

 thern Railway tunnels. 

 67-2 m. Toketic — Altitude 810 ft. (246-8 m.). At 

 108 • 1 km. Toketic a series of volcanic rocks commence 

 which have been correlated and mapped as the 

 Lower Volcanic group (Miocene?) by G. M. 

 Dawson, but regarding whose age there is 



