74 FACTS IN AMEEICAN MINING. 



Cement. — This material is crushed very coarse, passing through 

 a mesh of 8 to 16 holes to the inch, and a light stamper will crush 

 4 to 6 tons a day. 



Sea-sand, arising from the detritus of quartz reefs. — There are 

 cases in which the working of this material have been profitable. 



Ancient river beds — in some places a thousand feet deep. 

 One of the largest of these occurs in the Sierra Nevada country, 

 having a width of 100 to 300 yards, and a length of nearly 40 miles. 

 The amount of gold taken from this bed has never been ascer- 

 tained, but cannot be less than five millions sterling, and probably 

 twice as much. The modern streams run at right angles with the 

 ancient river bed. On the Tuolumne Table Mountain the basalt 

 was found to cover an ancient river bed to a depth of 300 to 1,000 

 feet. After years of work the channel was reached, and ten feet 

 square of washdirt yielded £20,000 ; a pint of gravel not unfre- 

 quently containing a pound of gold.* 



The auriferous belt in California extends about 250 miles in 

 length, with a width ranging from 25 to 50 miles. The veins in 

 this belt are innumerable — but the proportion producing payable 

 gold is very small ; the average width of all the veins examined is 

 about three feet, and the "country" rock either slate, granite, or 

 greenstone, but the most prolific of these formations is still unde- 

 termined. The mines frequently possess barren zones, both in 

 depth and longitudinal extension, but as frequently "make" again 

 in paying ground. 



* Ancient river beds. — In this country we have an ancient river bed'at Kiandra and the 

 vicinity, on the main Dividing Range ; the wash is 5 to 10 feet thick. The bed was originally 

 a river-wash, but it has become in places partially cemented with oxide of iron. It consists 

 partly of quartz, some of which is highly impregnated with copper. Single boulders of 

 quartz have been met with producing nearly a hundred pounds worth of gold. The rest of 

 the wash is made up of brecciated fragments of quartz, called by the miners "floating reef," 

 also slate, diorite, albite, felspar, hornblende, augite, &c. The average yield has scarcely been 

 ascertained as yet, and the bed of the ancient stream has not yet been reached. This river 

 bed has been traced about 30 miles, and again comes out in the Snowy Plains, in Victoria, 

 where the Government inteud to bore for, and prove it. A body of four men owning what 

 is known as the Scotchman's claim, at New Chum Hill, Kiandra, have driven into the hill 

 a distance of 1,300 feet, and now find that the wash has dipped away beneath them ; they 

 have already been ten years at work here, occasionally tapping some part of the wash over- 

 head. The total distance they have driven in all is about 2,300 feet, illustrating an extraordin- 

 ary case of perseverance under difficulties and privations in a most severe climate. This run of 

 partially cemented wash appears to have followed the main range, thus showing the great 

 alteration of the surface since its deposition. It is considerably above the level of the 

 surrounding country, and about 5,000 feet above the sea level. The bed rock of the country 

 at New Chum Hill is a mica slate, and strongly stained with oxide of iron. Just above the 

 deposit of wash is a bed of grey clay, about 12 feet in thickness ; above that a 30-feet bed of 

 lignite ; above that a bed 6 feet of clay — over the clay various layers of waterworn gravels, 

 capped by basalt, estimated to possess a thickness in some places of 500 feet. It is estimated 

 that this basalt covers a larger auriferous area than all the known Gold Felds in New South 

 Wales put together, though it is but little known at the present time. Starting from Snow}' 

 Plains, it comes out at Kiandra again on the Macquarie, through Mount Misery, on the 

 Rocky River, still following the main range; lastly we hear of gold under basalt on the 

 Palmer, still on the main range, while it is not improbable that it will be met with in New 

 Guinea. Both the basalt and the wash on the main Dividing Range, as well as the gold 

 itself, appear to be different in character from all other alluvial beds in the Colonies, and 

 point to their deposition in an earlier epoch. Most of the gold is coarse, some being found 

 in nuggets of one to two ounces, very little wateiworn, and largely alloyed with silver, its 

 value being only about £3 12s. Gd. per ounce. It is probable that many places will be found 

 auriferous along this range where the conditions are similar to those above described. 



