148 



THE AUEIFEEOUS GRAVELS OF THE SIEEEA NEVADA. 



That portion of the gravel lying to the north of the railroad to and including Dutch Flat and 

 Elmore Hill was not surveyed with the same minuteness as the portion which has been previously 

 referred to. This was owing partly to the fact that the rainy season seemed to be approaching and 

 our time was limited. It was, furthermore, not possible to get such trustworthy statistics of the 

 production of the district as were obtainable at Gold Bun ; and, as a consequence, there was less 

 need of minuteness of detail in the measurements. There has been no map made, so far as I know, 

 of the different claims in this district, — and in my own work I confined myself mainly to the 

 outlines of the portions actually worked out. The following statement, however, may be taken as 

 a pretty fair approximation to the actual gravel area which has been already washed over : 





Between the railroad and Squire's Canon 



Between Squire's Canon and Dutch Flat Canon .... 



In the main Dutch Flat Diggings between Dutch Flat Canon and Bear 



52 J acres or 2,286,900 square feet. 

 40 " 1,172,400 " 



a 



River . 



Total 



144 

 236| 



« 



a 



0,272,640 

 10,301,940 



it 



a 



a 



n 



The means for determining the average thickness of bank over this district are not so complete 

 and satisfactory as they were south of the railroad. The original country was more uneven, and 

 the outlines of the openings are not so regular as a whole. For the portion next north of the rail- 

 road I have adopted an average height of bank of forty-live feet. It is considerably higher than 

 that on the side next the track, but as I have included in my estimate of the area the long shallow 

 tongue through which an outlet is found into Squire's Canon, the calculated number of cubic yards 

 will be pretty nearly correct. 



Between Squire's Canon and Dutch Flat Canon there was originally a high hill of gravel which 

 has been so washed away that while we have on the southeast side of the excavations banks of a 

 hundred, a hundred and twenty-five and more feet, the northwest banks are almost nothing. If I 

 take an average of fifty feet for the whole area I think I am fully high enough. 



On Gray's Hill and the other hills which go to make up the gravel deposit between Dutch Flat 

 Canon and Bear River, it is even more difficult to decide upon a fair average depth. For the west- 

 ern quarter of the area, where the slope is more distinct from the top of Thompson's Hill towards 

 Dutch Flat Canon, or Bear River, and the banks are pretty high on the northwestern side, it seems 

 not far out of the way to take sixty-five feet for the average depth of gravel already washed away. 

 For the rest of the district I cannot speak with so much confidence. The few facts upon which a 

 judgment is to be based are as follows. The average height of the numerous projecting points on 

 the Bear River side of the diggings is about fifty feet above the present general level of the gravel. 

 Wear the town of Dutch Flat there is hardly any bank at all, — certainly not more than fifteen feet 





on the average. 



On the northeastern end, near the small reservoir, the bank is a little higher, 



say thirty feet ; and on the southwest, near Thompson's Hill, it will average as much as sixty feet. 

 The hill, however, rose considerably higher than the present level, — excepting perhaps on the 

 southwestern extremity. At the Dutch Flat Tunnel (referred to on page 151) Mr. Colgrove said 

 the top of the hill was from eighty to ninety feet above the present average gravel surface. At Mr. 

 Teaff's shaft (in Teaff's Diggings) there is a discharging tunnel, which was 206 feet below the 

 original surface of the ground, according to Mr. Julian's survey. This tunnel is still considerably 

 below the general level of the gravel. From such facts as these it is clear that the highest part of 

 the ground must have been somewhere between the site of the tunnel and Teaff's Shaft. For 

 the southwestern half of Gray's Hill I am inclined to accept an average depth of 100 feet, and 

 for the northeastern half an average depth of fifty feet, — or of seventy-five feet for the whole. 

 This would give us for the cubical contents the following results : — 



Between the railroad and Squire's Canon 

 Between. Squire's Canon and Dutch Flat Canon . 

 Between Dutch Flat Canon and Bear River (west |) 

 Between Dutch Flat Canon and Bear River (east |) 



102,910,500 



87,120,000 



101,930,400 

 352,836,000 



cubic feet 



a 



a 



a 



a 



a 



a 



Total 



644,796,900 



U 



U 



