312 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [March 8, 



middle of a river, unless there be a deep bed of boulders and gravel 

 for it to rest among ; and even then it is rare. 



The current has a tendency, derived from the more rapid motion 

 of the middle vrater, to drive all heavy matter towards its margin ; 

 but gold, being heaviest, resists more or less the force of the water, 

 and therefore remains towards the lower edge of the river's bank ; but 

 sand, being lightest, is driven highest up the bank ; and, as the river 

 continues to wear its bed deeper, or to work its way into the rock on 

 one side and leave a ledge on the other, in receding thus, it leaves a 

 bed of boulders and gravel in which gold may have been deposited. 



The river-workings, with few exceptions, having been failures, and 

 the winter now approaching, the miners left the streams to secure 

 ground in the " dry diggings " for winter work, and to build cabins 

 against the inclement season. 



So7iora Creek Diggings. — On the breaking-up of our company, I 

 returned to Sonora to obtain such information as I required to 

 determine my next proceedings, in which I resolved to be more than 

 usually cautious, as up to that time I had submitted to the judgment 

 of others, and had been unfortunate. Nor was my resolve weakened 

 on arriving at Sonora by finding the people at that place in a state of 

 excitement in consequence of the discovery of rich deposits of gold 

 in a spot that I had selected six months before, but had been pre- 

 vented from working by my partners having voted in favour of the 

 other ground at Sulivan's Creek. It was situated in the broad flat 

 bed of Sonora Creek, but just at a place where it contracted to enter 

 a narrower passage. A vein of greenstone crossed the river's course, 

 and stood above its slaty bed like a ledge, behind which a deep bed 

 of drift had collected ; and, as this drift had been brought down by 

 the stream from the rich country through which it passed, I had con- 

 jectured that rich deposits of gold might be found beneath it. As 

 soon as the discovery became known, the entire bank, amounting to 

 one and a half acres, was claimed, and divided into separate lots, of 

 ten feet square to a miner, all of which proved exceedingly rich. 



Campo Secho, and other diggings and quartz-ivorkings in the 

 neighbourhood. — I obtained employment at a place called Campo 

 Secho (Dry Camp) and remained there two months. The diggings 

 in that neighbourhood were of that description called " flats " (nearly 

 level enough to be termed plains) . The one in question (which was 

 being worked at different points) extends from Table INIountain to 

 Curtis' s Creek, a distance of about six miles from north to south, and 

 from one to one and a half in breadth, having a range of hUls on the 

 east side, and Wood's Creek on the west. 



Gold is found in greater or lesser quantity over the whole tract, 

 but chiefly about the water-courses by which it is intersected. 



The western border is composed of chlorite- slate ; and the eastern, 

 of micaceous slate ; the slates are vertical and in a state of rapid de- 

 composition. Where the micaceous slate approaches the surface, it 

 decomposes with a red colour like that of the earth with which it is 

 covered ; the plates or laminae of the rock become open and earthy 



