92 ALASKAN MINERAL RESOURCES IN 1906. 
which the oil has at times a considerable pressure, and two more wells 
in which an unknown amount of oil stands near the top of the casing. 
Drilling has proved to be very difficult and expensive and the 
results are not as encouraging as had been hoped. These facts, 
together with the uncertainty as to the amount of territory which 
one concern may legally control, and the equally great uncertainty as 
to the conditions of the market, have led to a suspension of some of 
the more active operations. 
The petroleum obtained in the region, both from the seepages and 
from the wells, is all a high-grade, light-gravity, refining oil, with ; 
paraffin base and high content of naphthas and burning oils. The 
character of the oil has already been described a by the writer and 
no new information is available. 
OCCURRENCE OF PETROLEUM. 
SEEPAGES. 
GEOGRAPHIC DISTRIBUTION. 
It may be seen from inspection of the map (fig. 1) that the seep- 
ages all occur within a long, narrow belt extending from the edge of 
the Copper River delta to Bering Glacier, a distance of about 28 miles 
from east to west. The belt is very narrow, not exceeding 4 miles at! 
the widest known point, and is parallel to the north shore of Controller 
Bay, which has the same east-west direction as the larger aspect of 
the shore of the Pacific Ocean between Copper River and Yakutat 
Bay. The seepages at Cape Yaktag 6 are also reported to lie on a line 
having the same direction as this and practically coinciding with it in 
extended position. Several of the smaller groups of seepages, such as 
the group on Redwood Creek and at the head of Katalla Slough, and 
those in the valleys of Burls and Chilkat creeks, and in the Nichawak 
region, have a distinct linear arrangement, each extending in a direc- 
tion of about N. 15° E. These lines coincide with the directions of 
the valleys in which they occur, and the relationship suggested is 
that either the position of the valley and that of the line of seepages 
are due to the same cause or that the former is the cause of the latter. 
RELATIONS TO KINDS OF ROCKS. 
The oil of the seepages reaches the surface through a variety < f 
rocks. (See pp. 93-95.) The seepages west of Katalla are associated 
with metamorphic rocks, the oil coming to the surface either through 
the joints and bedding or cleavage planes of the slate and graywacke 
or through surficial deposits which probably overlie such rocks. The 
a Bull. U. S. CJeol. Survey No. 2'A), L905, pp. .",7-58. 
b Locally known as Cape Yakataga. 
