672 W. H. PENNING ON THE GOLDPIELDS OF 



Both the granite and the stratified rocks of this region are tra- 

 versed by intrusive dykes of trap-rock, mostly diorite, some 

 narrow, others of great width, and frequently traceable at the 

 surface for many miles. The main dykes generally, but not always, 

 follow a nearly N. and S. line ; the branches run in various direc- 

 tions. 



4. Sections and " Reefs,^' a-f. — a. At the southern extremity 

 of the granite* some gold-mining has been carried on upon what is 

 known as "Moodie's Eeef." This "reef" is situated just N, of 

 " Crawford Creek " (so called on Loveday's map) which flows here 

 nearly E., then turns northward to join the Kaap Eiver. This creek 

 is really a very deep gorge ; on the south side the mountain rises to 

 perhaps 1500 feet in height; on the north along spur branches ont 

 from the mountain, also following an easterly direction, its ridge 

 gradually descending, but being at this point about 800 feet high. 

 It coincides with the strike of the beds, which are vertical, as the 

 creek coincides with this also until it rounds the end of the spur 

 and turns towards the flat to the north. A difiference in the com- 

 position of the beds has. doubtless, been the chief cause of the 

 formation of this steep and peculiar gorge, roughly parallel to 

 the boundary of the granite flat, from which it is separated only 

 by the narrow but lofty ridge along which some of the mines are 

 situated. 



The rocks of the ridge are schists, shales, cherts, and sandstones, 

 which strike a little S. of E., and have a dip of about 90"", that is, 

 they are nearly vertical. A bed, or " seam," of white crystalline 

 quartz occurs about the centre of the ridge, coinciding with it and 

 with the ordinary stratified rocks in strike and dip. 



The rocks of the mountain are principally cherts, with some 

 highly altered shales, the same in strike and dip as those of the 

 ridge. In the gorge are loose pieces of chlorite-schist, but that 

 rock was not seen here in place. 



A few miles to the south on the high lands, in a farm t cursorily 

 inspected, the rocks seen along the lines traversed were, in ascend- 

 ing order from the edge of the mountain, cherts, shales, and sand- 

 stones, schists and conglomerates. The beds strike E.S.E. and are 

 nearly vertical, but not quite so much so as nearer the granite ; they 

 dip about 85° to the S. 



" Moodie's Eeef" (so called) consists of a deposit of white crystal- 

 line quartz, of the kind known by miners as " sugary quartz," varying 

 from 1 foot to 2 feet wide, and interstratifiecl with the rocks of the 

 district. It might possibly happen for it to occupy such position even 

 if it were a true vein or lode ; but I must consider it as a hed of 

 auriferous quartz. It is just as much so as the schists and cherts 

 are beds, because in so many instances, and over so large an area, 

 gold-bearing deposits of quartz, whatever may be the strike and dip 

 of the beds, occupy a similar position. This is not by any means the 

 usual mode of occurrence of gold, which is mostly found in veins, 



* In Farm no. 492 on Loveday's map. 

 t No. 505 on Loveday's map. 



