50 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213. 
The Glenn Creek mining camp lies on the northern edge of an 
extensive lowland basin known as the Baker Flats. These flats, 
opposite Glenn Creek, have a width from north to south of from 7 to 
10 miles, but their greatest extension is in an east-west direction. 
This broad lowland is a depression which has been deeply filled b}^ 
fluvial deposits. Near the mouth of Eureka Creek a prospect hole 
penetrated 65 feet of gravel without reaching bed rock. Along its 
southern margin there is a range of low, flat- topped hills, which sep- 
arate it from the great lowland of the Lower Tanana, and through 
this range Baker Creek flows in a narrow gap. The creek forks just 
above this gap, and the eastern fork, which is the larger, is called the 
Hootlenana, while the western fork retains the name Baker Creek. 
Eureka Creek, which receives a large part of the drainage from the 
northern margin of the flats, enters Baker Creek near these forks. 
A broad bench was observed 100 to 200 feet above the valley level at 
the northern margin of Baker Flat. The gold placers thus far dis- 
covered are confined to a number of small creeks flowing into the 
Baker Flats from the north, and in the immediate vicinity of the Glenn 
Creek camp these streams are known lobe gold-bearing only Avhere 
they cnl across the above-mentioned bench. Several miles to the 
east Pioneer Creek and other tributaries of the Hootlenana are gold 
bearing and it is probable that the gold-bearing belt extends about 
20 miles along the north side of the Baker Flats, but it was notexam- 
ined by the writer except in the immediate vicinity of Glenn Creek. 
Active mining has been in progress on Minook Creek, near Ram- 
part, since 1 sin;, and the creek was probably prospected as early as 
1882. From Minook Creek as a center prospectors have extended 
their search across the divides in all directions. In the summer of 
1901 colors of gold were found on Eureka Creek and mining was 
attempted. Gold in paying quantities was discovered on Glenn Creek 
July 24, L901, by a miner who had a contract for supplying wood at 
the mine on Eureka Creek. Colors of gold, but not in paying quan- 
tities, had already been discovered on Rhode Island and Omega creeks 
in this region. 
GEOLOGY. 
In the vicinity of Rampart on the Yukon the bed rock consists of 
a series of volcanic rocks interbedded with siliceous slates and lime- 
stones, called by Spurr the Rampart series. a From fossils collected 
last season near Circle this terrane is believed to be of Devonian age. 
About 8 miles south of Rampart a series of siliceous slates, quartz- 
ites, and schists was found, which continues with more or less varia- 
tion across the divide to Glenn Creek. The relation of the Rampart 
series to this slate and schist series could not be determined with cer- 
o Spurr, J. E., Geology of the Yukon gold district, Alaska: Eighteenth Ann. Rept. U. S. Geol. 
Survey, Pt. II, pp. 155-169. 
