martin.] STRUCTURE OF CONTROLLER BAY REGION. 19 
era shore of Strawberry Harbor (PL III). The dip is everywhere 
toward this concavity, changing from southwest at Point Hey to 
southeast at Cave Point, indicating the presence of a pitching syn- 
cline, of wihch only the nose is on land. 
An outcrop at the lower edge of the abrupt slope rising from the 
tidal flat about halfway between Burls Creek and Mary Creek lias a 
strike N. 55° E. and a dip of 52° NW. This would not seem to readily 
fit into any of the general structure hitherto described, and can only 
be explained at present as a local variation in the eastern flank of the 
above-mentioned syncline. (See PL III.) 
Chilkat Creek, which occupies the valley between Bering River and 
Burls Creek, has exposed a great many excellent outcrops. It is evi- 
dent that a sharp anticline extends along the general line of this val- 
ley from northeast to southwest, the dip of the flanks averaging about 
45°. The center of the anticline is very steep and locally crumpled. 
The ridge east of this valley, between it and Bering River, is appar- 
ently synclinal, with a strike of about N. 40° E. This fold is very 
sharp along its axis, for the rocks at the mouth of Bering River stand 
vertical, though farther up the river the clip is 40° NW. 
The strike of the coal formation is, in general, from northeast to 
southwest; and the dip is to the northwest. There are certain varia- 
tions, but they appear to be due to local disturbances. The structure 
of the region as now known is chiefly monoclinal. The continua- 
tion of this feature to the southwest would carry the coal into the 
hills on the west shore of Bering Lake and on the west bank of 
Katalla River. No coal is known, however, in these hills, and the 
shales exposed on the Avest shore of the lake appear to be identical 
with those on the south shore, which have been described in the pre- 
ceding chapter as the Katalla formation. It is evident, therefore, 
that there is a line of faulting through the north end of the lake and 
parallel to the west shore. The coal is apparently absent to the west 
of this fault. It would appear from the dip that the Kushtaka forma- 
tion overlies the Katalla formation; there is, however, no positive 
proof that such is the case. No contact of the two has been observed, 
and there is no reason why other explanations of the existing phe- 
nomena may not be found. 
The monoclinal dip, which has been observed as continuing for sev- 
eral miles up the valley of Canyon Creek, would seem to indicate a 
thickness of many thousand feet in the Kushtaka coal measures. Sev- 
eral faults, however, were observed in the banks of Canyon Creek. 
and it may be that these are numerous enough or of sufficient displace- 
ment to cause the thickness of the formation to appear greatly 
increased. 
This monoclinal dip is apparently modified by only two folds 
within the region hitherto explored. There is one fault which prob- 
