'mm. in. I FOBTYMILE REGION. 47 
iixl containing quartz and calcite seams, and a formation consisting 
)f sandstone, sandy shales, and coal beds. 
The ridge between Franklin and Chicken Creeks is composed of 
rranular and porphyritic representatives of types ranging from 
lornblende-granite to quartz-diorite, those related to the latter type 
>eing tl' ( ' more common. These rocks also Conn the canyon wall <d' 
Mosquito Fork about -1 miles west of the Chicken, and occur again 
>n the ridge between Chicken and Lost Chicken creeks. The green- 
stone and related rocks, largely of tuffaceous origin, form the high 
idge east of the Chicken and are cut by dikes of the preceding types. 
)li vine-basalt occurs on Myers Fork, on the Lower portion of Stone- 
louse Creek, and on the east side of the Chicken about a mile below 
he Stonehouse. Tt apparently extends over the entire area west- 
ward from this latter point to the dioritic rocks on Mosquito Fork. 
Dark jointed shales with quartz and calcite seams overlie the por- 
phyry east of Stonehouse Creek and are of interest because gold has 
>een found in them. Sandstone, sandy shale, and coal beds occur at 
everal localities on Chicken Creek, and coal is sometimes the bed 
•ock on which the gold is found. The sandstone, the ferruginous 
iodides which it contains, and the sandy shales all contain badly pre- 
erved plant remains, and the formation is correlated provisionally 
rith similar occurrences near Eagle which belong to the Kenai 
ormation. 
The stream gravels, so far as known, lie on a bed rock of basalt, 
andstone, or coal. They include representatives of the different 
inds of bed rock occurring in the neighboring hills. There is a large 
»roportion of greenstone and much olivine basalt ; granular and por- 
hyritie varieties of the granodiorite type are abundant, and there 
some quartz, slate, sandstone, coal, and ferruginous nodules often 
ontaining fragments of dicotyledonous leaves. Pieces of marble and 
chist indicate the occurrence of a formation like that of Franklin 
reek somewhere within the valley. The depth to bed rock in the 
lain valley varies generally from to 45 feet. A layer of muck 22 
eet thick covers the gravels, often forming more than half the entire 
eposit on bed rock. The gravels var}^ from G to 20 feet in thick- 
ess and are found mostly on the west side of the stream to a distance 
f nearly 1.000 feet from it. They vary in size up to a foot or more 
diameter, and in the lower portion contain considerable clay, which 
ften acts as a gold robber by balling up in the sluice boxes. 
The pay is found mostly on bed rock, but sometimes extends into it 
id often above it, where it is found through 5 feet or more of the 
avel. Most of the work has been done on the west side at a consider - 
>le distance from the creek. Pay has been found to nearly the ex- 
•eme western limit of the gravel and over a width of 80 feet. The 
