The Tiger Creek Trail and the Potarn-Konawaruk Road. 167 



Near Hope Placer, and again near the Hospital, rocks are exposed 

 which consist of coarse-grained augite-gi-anophyre or (|uartz-diabase 

 infiltrated with carbonates, iron and copper pyrites, and galena. 

 Specimens from near the Hospital were assayed, and were found to yield 

 gold at the rate of thirty-three grains \)QV ton. The hillsides near here 

 are covered with ironstone-gravel, while the hills themselves are composed 

 of diabase. In the placers of the Rhodius Syndicate, especially in those 

 situated near the ravines on the hillsides, great boulders of diabase are of 

 fre(|uent occurrence. From thirteen to about fourteen and a half 

 miles along the road many exposures of coarse diabase, which in places 

 approaches the structure of gabbro, and of augite-granophyre are 

 exposed, whilst from here to the fifteenth mile the rocks seen are more 

 or less altered quartz-porphyrite and felsite. Jaspery tVlsite is present in 

 abundance in the gravels at the Strong Hope Placer. About half-way 

 between the fourteenth and fifteenth mile posts exposures of dark-brown 

 and purple, compact, or in places schistose, rocks are exposed, which much 

 resemble the rock seen on the Potaro Ptiver south-west of the mouth of the 

 Kuribrong. From about the fifteenth mile post to the Divide, a distance 

 of less than half a mile, the road-cuttings show diabase or its degradation- 

 products, whilst at the Divide diabase lies over quartz-porphyry. 

 Grreat boulders of diabase are of common occurrence in the placer- 

 gravels in this neighbourhood, especially, as at Dispute, near the heads 

 of the tributary creeks of the Mahdia. 



The upper part of the valley of the Mahdia runs between two 

 mountain ranges, the higher parts of which show bare precipitous clifis 

 standing out from the surrounding forest. The ranges appear to be 

 mainly of similar structure. The Eagle Mountain Range on the east 

 of the road is, up to an elevation of 1,300 feet, of diabase, immense 

 masses of which are seen in the gullies and creeks. At about this 

 elevation granitite-gneiss occurs, which has been carried up by the 

 diabase, and is from two to three hundred feet in thickness. From near 

 1,500 feet to the crest of the i-ange, a height of 2,150 feet above the 

 valley of the Mahdia, the rocks, including those of the precipitous 

 cliif -faces, are of coarse-textured diabase. The structure of the mountain 

 indicates that during the protrusion of the masses of basic rock, of 

 which the Eagle Mountain Range, and others which run parallel with 

 it, consist, a portion of the granitic country, through which the diabase 

 was thrust, was caught up in it. 



A neck of diabase joins the eastern and western ranges of 

 mountains at the Divide, and a very rocky path through abandoned 

 placer workings leads into the valley of the Minnehaha, a tributary of 

 the Konawaruk River, to which it flows in a south-easterly direction. 

 The Minnehaha has many tributary creeks, on which are aui'iferous 

 fluviatile deposits. The stream rapidly widens as it approaches the 

 Konawaruk, where it traverses broad flats where auriferous gravels 

 occur at considerable depths, which materially militate against the 

 profitable exploitation of this part of the district. 



