228 



Kilometres ^ e ^ on S Adams lake can be seen to separate 

 the main Shuswap lake from Little Shuswap lake. 



The smaller lake basin has been eroded in 

 Shuswap orthogneiss with the form and relations 

 of a large irregular laccolith cutting the Chase 

 quartzite and coarse mica schists of the same 

 habit as that characterizing the Salmon Arm 

 schists thermally metamorphosed. The lacco- 

 lith is itself gneissic. Its planes of schistosity, 

 like its contacts and the invaded sediments, 

 dip 55-60 to the N.N.W. The E.N.E. end 

 of the body is near Squilax; the W.S.W. end 

 appears on the ridge across the river from 

 Shuswap station. Where observed, the upper 

 contact of the laccolith is made with the Salmon 

 Arm(?) schists or with (intrusive?) greenstone 

 of Shuswap age. The schists below the lower 

 main contact are heavily injected with ortho- 

 91-9 m. gneiss sills, and at Stormont siding the massive 

 147-9 km. orthogneiss cross-cuts the sediments as a very 

 broad dyke extending southeastwardly through 

 the mountain. This 'dyke' may represent the 

 main feeder of the laccolith. 



Between Chase (94-0 m. — 151-3 km.) and 

 Shuswap station (95-9 m. — 154-3 km.), the 

 line nearly parallels the strike of the coarse 

 Salmon Arm schists. The cliffs east of Shuswap 

 are composed of the underlying, massive 

 Chase quartzite dipping 50° to the N.N.W. 

 (See page 123). 



A short distance beyond this station the 

 sediments are truncated by a homogeneous 

 granite, little strained and with other character- 

 istics of the post- Paleozoic (late Jurassic) batho- 

 liths. With its abrupt appearance the section 

 leaves the Shuswap terrane. 



Terraces become more and more prominent 

 features in the valley floor. Their material is 

 remarkably fine-textured, homogenous silt, show- 

 ing distinct, even, bedding. As Dawson recog- 

 nized long ago, it is clearly a lacustrine deposit 

 and dates from the late Pleistocene. Since the 

 silt was not deposited in the basin of Little 

 Shuswap lake, it is most probable that that 



