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

ROCKS EXPOSED ALONG THE COAST FROM COPALIS TO HOH HEAD.

The rocks exposed along the coast between Copalis and Hoh Head are believed to include the "supposed Cretaceous," the Queniult formation (now regarded by Arnold as of Miocene and Pliocene age), and beds of clay, sand, and gravel of Pleistocene age, in addition to a small upfaulted block of the metamorphic rocks in the vicinity of Point Grenville. Some of the rocks exposed at a few localities are very similar to those described by Arnold as belonging to the Clallam formation, of Oligocene and Miocene age.

From Copalis north to a point a short distance south of location A, near Copalis Rock, the beds exposed along the coast are almost flat-lying, poorly consolidated rocks of Pleistocene and Recent clay, sand, and gravel. The rock exposed at location A, near Copalis Rock, consists of a bluish sandy clay, which in places gives off an odor of petroleum. Large fragments of dark conglomerate, greenstone, gray limestone, and coarse gritty sandstone, all cut by thin irregular veins of quartz and calcite, are intermixed with the bluish sandy clay. These fragments come apparently from the "supposed Cretaceous," the same kind of rock as that which constitutes Copalis Rock, which lies about 1,200 feet from shore. The exposure here may be due to upfaulting of the "supposed Cretaceous" rocks or it may be due to a rough surface of the older rocks not wholly concealed by the Pleistocene cover. Owing to poor exposures it was not possible to measure the dip and strike. A well at this locality was drilled for oil in 1901 to a depth of 850 feet but without success, as stated on page 25.

Pleistocene clay, sand, and gravel, forming cliffs in places as much as 75 feet high, are fairly well exposed along the coast between Copalis Rock (location A) and a point about 1 mile east and slightly south of the extreme end of Point Grenville (location D). For the most part these beds lie flat, but here and there dips are noticeable. At location B soft yellow and gray sandstone that dips 3°-4° SE. and strikes N. 55° E. is exposed. About a mile farther north, at location C, the beds consist of chocolate-colored to yellowish, soft argillaceous and conglomeratic sandstone which dips about 4° NE. and strikes N. 65° W. Just north of the mouth of Moclips River the beds lie practically flat.

In the vicinity of Point Grenville (locations D and E) there are metamorphic rocks which are believed to be in an upfaulted block of the old metamorphic rocks that constitute the core of the Olympic Mountains. These strata which show along the coast from location D to location E are very much broken by faults. A number of large castle-like rocks, situated from a few hundred feet to possibly as much as a mile offshore, probably belong to the same formation. At location D numerous fragments of metamorphic rocks, some of which seem to be in place, lie along the beach. The beds dip 40° N. and strike N. 65° W. Little more need be said than that these old rocks which form Point Grenville consist partly of conglomerate sandstone, and slate, much faulted and broken and cut by veins of quartz.

In the southwestern part of sec. 18, T. 21 N., R. 12 W., a few hundred feet west of the road leading from Moclips to Taholah, some very much faulted rocks which are believed to be a part of the Queniult formation are exposed. These rocks are situated about halfway between location D and the southern extremity of Point Grenville. At location E there is evidence of a fault trending approximately N. 40° W., separating the older rocks from the Queniult formation to the north. Directly north of this fault there is a prominent slide due to fractures in the strata adjacent to the fault.

Between locations E and F strata of the Queniult formation are well exposed. For a short distance north of location E the beds consist of yellowish-gray conglomeratic sandstone that lies almost horizontal for about 200 yards; the dip then increases gradually to as much as 25° N. and the strike is N. 85° W. A short distance farther north an overlying soft, friable concretionary yellowish-gray sandstone dips only 21° and strikes practically east. A short distance south of the point where the Taholah-Moclips road descends to the beach the massive conglomeratic sandstone beds of the Queniult formation are terminated abruptly by a small fault. For a short distance north of the fault along the coast they seem to be replaced by soft, sandy clay, gravel, and conglomerate which lie nearly flat. A little farther north the dip of these beds increases from 5° to 25° S., thus forming a small syncline a short distance south of the point where the road leaves the beach between locations E and F. The Queniult formation in this locality is stained a yellowish color by limonite, which has seeped from the overlying Pleistocene beds. Between the point where the Moclips-Taholah road descends from the upland to the beach and location F these strata are very much disturbed, being broken by small faults and folds and in places dipping as much as 62° NE. From point Grenville to location F these rocks are capped by Pleistocene clay, sand, and gravel, in places as much as 100 feet thick. Near the base of this material springs are fairly numerous. Between location F and Taholah the surface rocks along the coast consist of Pleistocene and Recent sand, gravel, and clay. From location G, just north of the mouth of Queniult River, to location H, about a mile north of Cape Elizabeth, the Queniult formation is again well exposed. At location G the formation consists of yellowish-gray sandstone and conglomerate interbedded. Conglomerate seems to be more abundant in this locality than in the same formation south of the river. A short distance north of location G the beds dip 21° SE. and strike N. 35° E. About one-fourth mile northwest of location G the beds dip about 13° SE. and strike N. 60° E. From this point northwestward the beds dip at slight angles to the south and then gradually flatten and continue nearly horizontal to a point a short distance south of location H, where the dip increases to 10° SE. and the strike is N. 20° E., the bed being approximately the same as that on which the dip and strike were measured at location G. Just south of location H the Queniult formation dips 17° SE. and strikes N. 35° E.

As stated on page 28, the Indian Oil Co. is drilling a well at a point about one-half mile north of location G. The rocks penetrated in the greater part of the well are the same as those exposed on the coast between locations G and H, whereas the black shale at the bottom of the section may be represented at the surface by the dark shale that outcrops in the vicinity of location H. The record of the well given below states the character and thickness of the strata penetrated and also indicates at what depths gas and traces of oil were encountered.

Log of the Indian Oil Co.'s well, in the NW. 1/4 sec. 35, T. 2 N., R. 13 W., near Taholah.
[Compiled from the driller's statement.]

At location H and to the north, for about 1,500 feet along the beach, rocks are exposed which are different from those along the beach, between locations G and H. These rocks consist of bluish sandy shale and shaly sandstone interbedded and are somewhat faulted and inclined at different angles. At one place the beds dip 32-1/2° NE. and strike N. 60° W., but in most places it was impossible to obtain good measurements of the dip and strike, owing to slumping and the presence of faults. It is believed that these beds of bluish shale are included in an upfaulted block of the "supposed Cretaceous" of Arnold's classification. The exposures along the coast afford no indication of the inland extent or direction of these faults.

The rocks lying north of the blue shale described above, situated near location H, are in many respects similar to those exposed between locations E and F, south of the mouth of Queniult River. A few hundred feet south of location I, near the point at which the horse trail descends to the beach, beds of sandstone that dip 31° S. and strike N. 75° E. are exposed. Approximately at location I bluish sandy clay interbedded with yellowish argillaceous sandstone is exposed. These beds dip 19° SE. and strike N. 27° E. A little farther north along the coast soft, friable argillaceous, almost massive sandstone, containing much mica and some concretions, outcrops. It dips 26° SE. and strikes N. 15° E. A short distance north of location I there is an abrupt change in structure, the beds dipping 18° E. and striking N. 5° W. The character of the rocks on which the above measurements were taken is practically the same as that of the rocks at location I.

At location J, in the SW. 1/4 sec. 15, T. 22 N., R. 13 W., beds of soft, friable yellowish-gray sandstone are fairly well exposed. They dip 39° SE. and strike N. 50° E. About three-fourths of a mile farther north, at location K, directly north of the mouth of Camp Creek, the formation consists of soft gray sandstone containing concretionary lenses of hard calcareous sandstone. The surface of these beds is stained yellow in many places with limonite. The strata dip 57° SE. and strike N. 27° E. From location K northward along the coast to location L, in the northeastern part of sec. 4, T. 22 N., R. 13 W., the same formation is fairly well exposed. At one place about 1 mile north of location K the beds dip 47° E. and strike N. 10° E. A measurement was made just south of the point where the trail descends to the beach at location L, which shows that the beds dip 10° E. and strike N. 5° E. The rocks consist of friable argillaceous sandstone containing small gray clay balls and a few pebbles of harder material. A short distance, possibly 600 or 800 feet north of location L, the same formation dips 28° SE. and strikes N. 15° E. The rocks at this place more nearly resemble the rocks exposed on the coast near Copalis Rock, location A, a few miles north of Copalis, than do any of the strata exposed between locations A and L. A few hundred feet north of location M, just south of the "Little Hogback," dark sandy clay having an odor of petroleum is exposed. In traversing the coast the writer made a careful examination for this "smell mud," but at no place between locations A and M is any known to be present. The rocks along the sea cliff in this part of the coast have slumped considerably, and in places the unconsolidated Pleistocene materials are intermixed with rocks slumped from the older formations. At some places the strata are very much disturbed by small folds and faults. Just north of the "Little Hogback," at location M, the strata dip 60° SE. and strike N. 35° E. Between location N and the mouth of Raft River the rocks are fairly well exposed. Just south of the mouth of this stream there is a hold promontory which at high tide is practically an island and in which the water has worn large cavities and tunnels. On this promontory the strata are much contorted, forming, in a distance of 150 yards, two small synclines with an anticline between them. The general dip of the strata at this place is 50° NW. and the strike N. 65° E. Just north of Raft River a massive grayish-blue sandstone is well exposed in a high cliff. It was impossible on account of the massive character of the rock to determine the dip and strike on this outcrop. On one of the small islands near shore, however, the beds dip 53° NW. and strike N. 25° E. About 600 or 800 feet north of the mouth of Raft River a prominent fault trends approximately N. 80° W. and cuts out on the north the massive grayish-blue sandstone described above. The inclination of the fault plane is almost vertical. North of this fault there is a zone about 50 feet wide in which the rocks are very much crushed, so that the dip of the strata could not be determined. These strata in places give off the odor of petroleum. Between locations O and P, a short distance south of the mouth of Kalaloch Creek, the rocks consist of nearly flat-lying beds of clay, sand, and gravel of Pleistocene age, which are stained yellow here and there by limonitic water. A thin bed of very poor lignite is present in these beds about half a mile north of the mouth of Quail Creek.

At location P, just south of the mouth of Kalaloch Creek and about 100 yards from the water's edge at low tide, a massive grayish-brown sandstone, stained yellow in places, is fairly well exposed. It is so massive that it is impossible to determine its dip and strike. The rocks exposed along the coast for about a mile north of the mouth of Kalaloch Creek consist of Pleistocene clay, sand, and gravel, which in places contain some lignite. The best exposure of this material was noted just south of location Q, in the NW. 1/4 NE. 1/4 sec. 4, T. 24 N., R. 13 W. The greatest thickness of the lignite is 5 feet and it is very impure. It contains many roots, stumps, and branches of trees which have been but slightly altered since their deposition. The cliff at this place is about 60 feet high and is made up of flat-lying strata of Pleistocene age. A short distance north of location Q "supposed Cretaceous" strata are well exposed. They consist of alternating thin beds of dark and light sandy shale and shaly sandstone from 2 to 3 inches in thickness, which dip 50° E. and strike approximately north. For a mile or more to the north along the coast the same formation is well exposed, but at location R these beds abruptly give place to the unconsolidated Pleistocene material for about one-third of a mile. At location R the strata dip 38° SE. and strike N. 12° E. The rocks exposed at location R, just south of the place where the Queets-Hoh trail descends to the beach, consist of coarse yellowish-brown massive sandstone that contains in places a few pebbles and some hard brown spherical and irregularly shaped concretions, the cementing material of which is iron. At location S, near the center of sec. 28, T. 25 N., R. 13 W., the medium-bedded, yellowish gray "supposed Cretaceous" sandstone, much folded and in places possibly cut by slight faults, is again exposed, dipping in general 55° SE. and striking N. 25° E. At location T, about one-half mile north of location S, the sandstone is yellowish brown, coarse grained, and in places conglomeratic. It dips about 77° SE. and strikes N. 15° E. About one-third of a mile north of location T the beds are also very much disturbed. At one place about 100 yards north of location T the rocks consist of alternating beds of sandstone and shale, which dip 47° SE. and strike N. 18° E. At another place near by hard gray sandstone, locally stained yellow, dips 82° SE. and strikes N. 15° E. At this place all the strata are overlain unconformably by the Pleistocene beds, which in addition to clay, sand, and gravel contain 3 to 4 feet of poor lignite. A short distance farther north the "supposed Cretaceous" beds are vertical and strike N. 70° E. These beds extend along the coast to location U, in the NE. 1/4 NW. 1/4 sec. 21, T. 25 N., R. 13 W. Northwestward from location U to location V, a short distance north of the mouth of Steamboat Creek, the rocks exposed at the surface consist of clay, sand, and gravel of Pleistocene age. Just north of location V there are exposed thin alternating beds of sandy shale and shaly sandstone of different colors, in appearance resembling somewhat the stripes in a flag. The beds at location V, which are similar to the beds exposed at location Q, dip 60° E. and strike N. 8° E. At various places from location V northward to the mouth of Cedar Creek "supposed Cretaceous" rocks are exposed at low tide. They are quite hard, much jointed, and fractured, so that reliable dip and strike readings are difficult to obtain. At location W, just south of the mouth of Cedar Creek, prominent dark conglomerate in columnar form projects from the sand and gravel along the beach. The pebbles contained in the conglomerate are of different colors, ranging from white though gray and yellow to brown, and the largest are one-third of an inch in diameter. These pebbles resemble in size and appearance the gravel brought up by the bailer from a depth of 450 feet in the Jefferson Oil Co.'s well, a few miles to the northwest. The dip of the strata at location W is approximately 40° NW. and the strike is N. 73° E. This dip and strike measurement was obtained on a prominent mass of rock which extends into the ocean 100 yards north of the mouth of Cedar Creek and which at high tide is an island but at low tide is connected with the mainland. Just north of the mouth of Cedar Creek the soft sandy clay resulting from the weathering of the "supposed Cretaceous" rocks gives off an odor of petroleum and is the characteristic "smell mud" of this general region. Yellowish-gray sandstone of the same formation as that above described is exposed about one-half mile north of the mouth of Cedar Creek. It dips 33° N. and strikes N. 80° E. For about a mile along the coast northward from this point the surface rocks are of Pleistocene age. They form a cliff 100 to 150 feet in height, from which large slides have occurred in the poorly consolidated sand and gravel. From the north end of this exposure, at location X, to a point about one-fourth of a mile south of the mouth of Hoh River, sandy clay very much disturbed by slumps and slides is exposed. It was impossible to obtain any dip and strike readings on these rocks, but at location Y, just east of the old dance hall at the Hoh Indian village, the strata are well exposed, dipping 29° E. and striking N. 10° W. About one-fourth of a mile south of location Y "smell mud" is plentiful. It is reported that oil seeped from this sandy clay profusely until it was covered by a slide that occurred a few months previous to the time of the writer's visit. Since that time no one has been able to discover any evidence of oil issuing from the sea cliff.

Between the mouth of Hoh River and a point on the beach about 1 mile north of Hoh Head, near the center of sec. 2, T. 26 N., R. 14 W., the "supposed Cretaceous" rocks are well exposed. The most prominent feature is a narrow anticline, the axis of which extends in a northeast-southwest direction through the northern part of sec. 13 and the southern part of sec. 12 of the same township, and presumably though the center of sec. 7, T. 26 N., R. 13 W. At location Z, in the SW. 1/4 SW. 1/4 sec. 18, T. 26 N., R. 13 W., "smell mud" is very plentiful. At this place the rocks which give off the odor of petroleum consist of alternating "flaglike" beds of yellowish-gray argillaceous sandstone and chocolate-brown soft clay shale. These beds are folded and disturbed, so that a reliable measurement of the dip and strike could not be made. Just northwest of location Z there is a very narrow anticline. The strata near location Z dip about 41° NE. and strike N. 40° W., whereas a little farther north the dip is 54° NE. and the strike N. 50° W. There are so many small folds and faults that no two measurements of the dip and strike agree. Near this locality and about one-third of a mile north of the mouth of Hoh River a dip of 26° N. and strike of N. 80° W. was measured on a bed of greenish-gray sandstone overlain by coarse sandstone and conglomerate, the largest bowlders of which are 18 inches in diameter. A short distance south at low tide it was possible to determine that the beds flatten to a dip of 15° N. and the strike changes from N. 80° W. to N. 80° E. on the same stratum.

At location AA, a few hundred feet northwest of location Z, beds of resistant conglomerate and greenish-gray sandstone are well exposed. The sandstone, in the form of small lenses and beds 40 to 60 feet thick, is interbedded with the conglomerate, which is composed of pebbles and bowlders ranging in size from sand grains to bowlders 3 feet in diameter. The beds are much jointed and folded, and at one point on the south flank of the major anticline on which the Jefferson Oil Co.'s seep is situated they dip about 77° SW. and strike N. 55° W.

The rocks exposed at location BB consist of bluish-gray argillaceous sandstone and interbedded thin sandy shale, which dip 40° SE. and strike N. 35° E. Approximately 75 per cent of the mass is sandstone and the remainder is shale. All these rocks are much jointed and slickensided, showing that they have been subjected to great pressure and movement. Owing to the presence of slides and slumps of "supposed Cretaceous" rocks and also of the overlying Pleistocene material, exposures are poor for about one-third of a mile north of this outcrop and almost an equal distance to the south.

The Jefferson Oil Co. drilled a well to a depth of 868 feet at a point about one-third of a mile north of location BB. The section of strata penetrated by the drill is as follows:

Log of the Jefferson Oil Co.'s well at Hoh Head, in the SW. 1/4 SE. 1/4 sec. 12, T. 26 N., R. 14 W
[Drillers' record.]

The section of strata exposed in the shaft at the Jefferson Oil Co.'s seep a few hundred feet north of the well is as follows:

Section of strata in the Jefferson Oil Co.'s shaft in the NW. 1/4 SE. 1/4 sec. 12, T. 26 N., R. 14 W.

The oil seeps from the lower bluish sandy shale and is not present in appreciable quantities in the overlying yellowish clay.

The rocks at location CC, just south of Hoh Head, lie on the north flank of the prominent anticline referred to above. They consist of brownish-gray sandstone interbedded with a small proportion of dark carbonaceous shale. In places the strata are broken by small faults which cut the rocks obliquely to the bedding planes. Lenses of conglomerate, consisting of pebbles and bowlders of bluish-gray sandstone, sandy clay, limestone, and quartzite with much lime and iron in the cement are present in the sandstones. Minute veinlets and stringers of calcite or quartz cut all the strata. A little coal (as much as one-half inch thick in places) also occurs in these beds. The strata on the beach dip about 80° NW. and strike N. 28° E., whereas on the hillside, about 100 feet higher, the beds consist of alternating layers of yellowish-brown and gray sandstone and sandy shale which dip 41° NW. and strike N. 15° E.

On the north side of Hoh Head, a few feet east of the trail and possibly a hundred yards from the ocean, a small landslide has exposed bluish sandy shale which gives off the odor of petroleum. It was not possible to measure the dip and strike of these beds. The rocks exposed on the beach just east of location DD consist of bluish-gray sandstone and sandy shale, which weather into bluish sandy mud and in places give off the odor of petroleum. At location DD, on the north side of Hoh Head, several hundred feet of yellowish-brown, somewhat argillaceous sandstone is exposed, dipping approximately 45° SW. and striking N. 65° W. At location EE, which is almost 1 mile north of Hoh Head, gray carbonaceous and argillaceous sandstone containing thin lenses of coaly material one-half inch in maximum thickness is exposed. The general dip of the strata here is approximately 60° E. and the strike is N. 10° W. Some small faults cut the rocks in this locality.

Location EE is the northernmost point along the coast visited by the writer. The rocks exposed farther along the coast for a mile or more apparently belong to the same formation as do those in the vicinity of Hoh Head.

To summarize, the oldest rocks exposed along the coast between locations A and EE are at Point Grenville. Here the old metamorphic series has been upfaulted and is represented not only by the rocks exposed between locations D and E, but also by those very resistant rocks which form the numerous islands in this locality a mile or more from the coast.

The "supposed Cretaceous" rocks are believed not to outcrop south of location H, about 3 miles northwest of Taholah, except possibly at location A, near Copalis Rock. From present knowledge it seems very probable that practically all the strata, with the exception of the Pleistocene clay, sand, and gravel discussed below, that outcrop along the coast between locations H and EE belong to the "supposed Cretaceous" formation. The only other outcrop of rocks of probably the same age are those exposed in a very small area just east of Copalis Rock at location A.

The Queniult formation outcrops in the vicinity of the mouth of Queniult River, between locations E and H. As stated above, some of the rocks exposed in the vicinity of locations J and K very much resemble the Queniult formation at its type locality.

The Pleistocene beds are exposed almost continuously from Copalis northwestward to location D near Point Grenville, and are again exposed continuously for a number of miles in the vicinity of the mouth of Queets River from location O to location Q, with the exception of a small isolated outcrop of "supposed Cretaceous" rocks just south of the mouth of Kalaloch Creek. Farther north along the coast they are also exposed between locations R and S, in the southern part of sec. 28, T. 25 N., R. 13 W., for about one-half mile, and again for a mile or more directly southeast of the mouth of Steamboat Creek, between locations U and V. From a point about one-half mile north of location W, near the mouth of Cedar Creek, the Pleistocene beds are well exposed northward as far as location X. In addition to the exposures along the coast the Pleistocene caps practically all of the exposures of the Queniult formation and the "supposed Cretaceous" rocks.