FORMER THEORIES IN REGARD TO THE GRAVEL DEPOSITS. 



67 



newspapers in regard to this question, — as well as about the origin of the 

 gold in the different formations. The idea that these immense gravel accu- 

 mulations were in some way the result of ancient river action began to gain 

 ground, although vehemently opposed by many. It is very easy at the pres- 

 ent time to understand the cause of the great diversity of opinion among 

 the miners. The idea of an ancient river formation was at first always 

 connected with the existence of one river, and not of many. This arose 

 from the fact that the high gravels were exposed, during the earlier years of 



hydraulic mining, chiefly along a certain belt of the Sierra, at various points 

 of nearly equal height above the sea, exhibiting at these points very simi- 

 lar appearances, so that they seemed to be portions of one consecutive 

 formation crossing the present system of rivers nearly at right-angles. 



Thus Dr. J. 13. Trask, who conducted a geological reconnaissance of 

 the State, under authority of the Legislature, during the years 1852-55, 

 in his second Report of work done in 1853, speaks of an ancient stream 

 flowing with a breadth of about four miles, at an elevation of 4,000 feet 

 above the sea, from Butte to El Dorado County.* This stream he calls 

 the " Eastern Blue Range/' and he describes its peculiarities with con- 

 siderable detail, tracing it from the South Pork of Feather River as 

 for as Georgetown. According to Dr. Trask, the boulders found in this 

 lange of gravel are almost exclusively quartz, surrounded by an earthy 

 material of a deep blue color, giving a very marked character to the 



* 



" It is now ascertained to a certainty that the placer-ranges extend to the east, within ten or fifteen 

 miles of the * Summit Ridge/ so called, of the Sierra Nevada ; and the condition in which it is found at 

 these points are similar in all respects to that in the older or more western sections, with perhaps one ex- 

 ception, and that the relative age of both. There are evidences which clearly indicate a deposit of gold 

 older than the diluvial drift of the lower or western diggings (which latter is often confounded with the 

 drift deposits of the tertiary periods in this country), the character of whicli differs in almost every respect 

 from any other deposit yet observed in this country, except in this particular range. Its direction has 

 been traced for about seventy miles, and is found to extend through the counties of Built 1 , the eastern part 

 °f Yuba, Sierra, Nevada, Placer, and El Dorado ; it appears to have an average breadth of about four 

 niles, willi an elevation of four thousand feet above the sen. for the greatest part of its length. From (he 

 examinations that were made upon this range, there arc abundant evidences that an ancient stream flowed 

 trough this section of the country, and in a direction parallel with its then existing mountain ridges, and 

 the extensive mining operations conducted in the southeast part of Sierra County on this range, has been 

 the means of demonstrating tins fact, which had heretofore been strongly suspected only. The outliers of 

 its banks are very definitely marked throughout the entire length of the formation under consideration, 

 ' uul its former bed filled in many places with a volcanic sand and ashes, which probably accompanied its 

 ^placement." — J. B. Trask, M. D., in Report on the Geology of the Coast Mountains and Part of the 

 Siena Nevada, Doc. No. <), Session 1854. pp. 61, 62. 



i 



