CHAPTEK XIX. 



THE KONAWARUK RIVER. 



The structure of the Konawaruk River is well seen whilst descending 

 the river from the southern end of the valley of the Minnehaha to the 

 Potaro River. Near the junction of the Minnehaha with a tributary 

 of the Konawaruk, and at Two Mouth, where the latter joins the main 

 river, the rocks exposed are dark-coloured porphyrites with dykes of 

 epidiorite and of diabase. From Two Mouth to Jordan's Landing, 

 a distance of about four miles, the river generally has an easterly 

 direction, and but few exposures of rock are seei\, the bed of the 

 river being covered with sand and its course frequently interrupted 

 by many fallen trees locally known as " tacoubas." The rocks 

 exposed consist of granitite, varying somewhat in texture but generally 

 coarse-grained, intersected in places by narrow dykes of fine-grained 

 diabase, which near contact with the granitite is changed into 

 compact epidiorite. The placers near Jordan's Landing are worked in 

 angular quartz-gravel, here and there containing boulders of diabase and 

 of epidiorite. The path from Jordan's Landing to the Potaro Road, 

 which crosses over the Eagle Mountain range, runs over hills of 

 diabase covered with concretionary ironstone and red clay — its 

 degradation products. 



From Jordan's Landing the river flows in a generally north- 

 easterly direction through a valley, the bottom of which is filled 

 with alluvial and fluviatile deposits, deep sections of these deposits 

 being exposed in many places along its tortuous course, chiefly in 

 its upper reaches. For about half a mile from Jordan's Landing, with 

 the exception of local deposits of concretionary ironstone, grey granitite 

 is the only rock seen. For the next mile the bed of the river 

 is covered with sandbanks, no rocks being seen until a dyke of an 

 augite-granophyre trending west-north-west and east -south-east crosses 

 the river. Parallel to this, and apparently in contact with it, a broad 

 belt of biotite-porphyrite, probably from four to five hundred feet across, 

 is well seen on the south-west bank a little below an itabo through 

 which boats have to pass when the river is low. A great mass juts out 

 into the main stream, and consists of a porphyritic rock with crystals of 

 greenish and of light-pink feldspar in a dark-grey groundinass, with here 

 and there nests of chlorite, biotite and epidote. The rock is identical 

 in character and appearance with one collected Ijy Mr. Anderson from 

 near Ironside Placer on the Minnehaha Creek. 



