Geological Survey Bulletin 581—B Oil and Gas in the Western Part of the Olympic Peninsula, Washington

The writer does not predict that oil will be found in commercial quantities in this field, but he firmly believes that it is a region worthy of the attention of oil operators.

The report does not attempt to describe the stratigraphy and structure of all the rocks exposed in the area represented by Plate II, hut it does set forth all data collected in this field during the two months' reconnaissance.

It is significant that all places where oil is escaping from the surface of the earth, either in seeps or in oil-saturated sandy clay, and the principal places where gas is escaping are situated in that part of the field where the older "supposed Cretaceous" and Tertiary rocks are exposed. It is believed that the source of the gas at the Garfield gas mound is not in the Queniult formation, through which it issues to the surface, but in the underlying "supposed Cretaceous" formation. The gas escaping in Queniult Lake issues from a place where marsh gas is naturally expected to occur, namely, at the mouths of streams which have carried and buried and are continuing to carry and bury large quantities of vegetation, the decomposition of which could easily explain the large quantities of escaping gas. As this gas was not analyzed, it is impossible to state definitely whether it is natural gas or marsh gas. The location of the vents suggests marsh gas.

In this field, as has already been pointed out, the oil seeps and occurrences of "smell mud" are firmly believed to be situated near the crests of anticlines. The gas vents are not similarly located because, as has been shown, the gas escaping at the Devils Mush Pot, near Spruce post office, on Hoh River, is certainly not associated with the crest of an anticline of the rocks which outcrop just to the west. It is also true that the gas escaping at the Garfield gas mound is not situated near the crest of any known anticline. However, it may be situated near the crest of an anticline of the underlying "supposed Cretaceous" rocks, which are believed to be unconformably overlain by the Queniult and younger formations. As the rocks of this field, which lies in that part of the United States where the annual rainfall is greatest, are undoubtedly well saturated with water, and as the principal oil seeps are situated near the crests of anticlines, it seems advisable for those desiring to exploit the oil and gas resources of the region to drill in the vicinity of the crests of an anticline rather than in a syncline or where monoclinal dips prevail.

The structure of rocks along the various river basins have been considered by districts. That discussion, together with dip and strike symbols and the lines representing axes of anticlines shown on the map (Pl. II), should be a guide in a very general way to those contemplating drilling. It should be kept in mind, however, that the presence of favorable structures, such as anticlines and domes, is not absolute proof that oil will be found. It is fairly safe to assume that if the oil is not discovered where the structure is favorable the chances are very remote that it will be discovered where the structure is positively unfavorable.

The discovery in this region and in commercial quantities of oil similar to that issuing from the seeps near Hoh Head would undoubtedly prove to be a great boon to the Olympic Peninsula in that it would be a means of opening this comparatively unknown region to settlement. From the rainfall, the character of the soil, the numerous water-power sites, and other natural advantages, it seems quite probable that this region may in time furnish homes for thousands.