laiometres steamer enters Swanson channel between Pre- 

 vost island on the northwest and Pender island 

 on the southeast On these islands, the Nanaimo 

 sediments, which are stratigraphically of a 

 lower horizon than on Galiano and Mayne 

 islands, are rather closely folded so that the dips 

 are variable and fairly high. Seen in the back- 

 ground to the south and west of Prevost island 

 is Saltspring island, the largest of the many 

 islands off the east coast of Vancouver island. 

 Its southern and central part is composed 

 largely of the metamorphic rocks of the Van- 

 couver group with intrusive bodies of grano- 

 diorite. Upon these the Nanaimo series lie 

 unconformably, the basal members being strati- 

 graphically considerably above the base of the 

 series in other localities. The metamorphic 

 and granitic rocks are seen surmounting the 

 Nanaimo sediments, attaining an elevation of 

 about 2,300 feet (700 m.), although the average 

 elevation of the comparatively smooth top, 

 which is a part of the uplifted Tertiary pene- 

 plain, is about 1,500 to 1,800 feet (450 to 540 m.). 

 A low valley underlain by Nanaimo shales 

 crosses the upland, and is bounded on the north 

 by a steep slope. This slope, which is underlain 

 by the metamorphic rocks with a cap of basal 

 conglomerates, has been developed along an 

 old fault, which separates the Nanaimo shales 

 from the upthrown metamorphics. The original 

 fault scarp was destroyed during the Tertiary 

 erosion cycle, but after the uplift of the 

 Tertiary peneplain, the less resistant Nanaimo 

 sediments were more rapidly eroded leaving 

 the metamorphics again in relief and pro- 

 ducing a new scarp, a fault line scarp along the 

 old fault. 



Leaving Swanson channel, the steamer enters 

 Moresby passage between Portland island to 

 the west and Moresby island to the east. 

 Both islands consist largely of the older 

 metamorphics (Sicker series) and intrusive 

 granodiorites, although small areas of Nanaimo 

 sediments rest unconformably upon these older 



