82 AURIFEROUS GRAVELS OF THE SIERRA NEVADA. 
subject will be essentially that of Mr. Goodyear’s route in the field, and may 
be followed on the accompanying sketch-map showing the distribution of 
the Volcanic and Gravel Formations over a portion of Placer and El Dorado 
counties. (Plate B.) This map is an approximation only for the region high 
up among the numerous branches of the Middle Fork of the American River, 
that district never having been topographically surveyed. A portion of El 
Dorado County, south of the Middle Fork of the American, — which separates 
El Dorado from Placer County, — extending as far south as Georgetown, 
is also to be found on this diagram; but the region east of this, at the head 
of the South Fork of the Middle Fork —also visited by Mr. Goodyear — 
has been omitted for want of the necessary data. For the immediate vicinity 
of Placerville — an interesting and important mining district —a special 
sketch-map, on a scale of three miles to the inch, is introduced. 
The route pursued by Mr. Goodyear in his investigations was nearly as 
follows: From Colfax across the North Fork of the American to Jowa Hill, 
Wisconsin Hill, Elizabeth Hill, Sucker Flat, Monona, Wolverine, Strawberry, 
and the other important mining towns between the American and the branch 
of it called Shirt Tail Cation; then to Damascus and the Forks House, near 
the head of Shirt Tail; then to Canada Hill, Millers’ Defeat, Last Chance, 
and the other mining camps at the head of the North Fork of the Middle Fork 
of the American; from the head of the Middle Fork down to Deadwood 
and Michigan Bluff, respectively on the east and west sides of El Dorado 
Caiion, thence down the south side of the divide between the Middle Fork 
and Shirt Tail, through the extremely important mining localities between 
Michigan Bluff and Todd’s Valley, including Bath, Forest Hill, the Dardanelles, 
and Todd’s Valley. From Forest Hill the north side of the same divide was 
visited, including Yankee Jim’s and the different branches of Brushy Cajon. 
Crossing the Middle Fork of the American, Mr. Goodyear’s route next took 
him to the mining districts along the divide north of Otter Creek, to Voleano- 
ville, and to the various localities north of Georgetown, on both sides of 
Cation Creek. At this point the work was suspended for a short time, in 
order to refit and repair. On recommencing, a start was again made from 
Colfax, and some localities about Iowa Hill, Forest Hill, and Michigan Bluff 
were revisited. Another trip was also made to the region high up on the 
Middle Fork, about Last Chance and Startown; thence down the valley to 
Peckham Hill, and across the Middle Fork to Spanish Dry Diggings, and by 
way of Greenwood to Georgetown again. From the last-named place an 
