LATER TERTIARY (MIOCENE AND PLIOCENE). 833 



The sandstones of the Clallam formation are for the most part thm bedded, hard, and 

 resistant to erosion and are extremely fossiliferous in certain locahties, notably east of ClaUam 

 Bay. They are found at the base and near the top of the Cape Flattery section and below 

 the upper conglomerates east of Clallam Bay. 



The shale of the Oligocene-Miocene occurs principally in the middle of the formation along 

 the strait. The lower part of the shale is thinly and plainly laminated, but higher up becomes 

 almost massive clay. * * * The overthrusting of the beds exhibited at [one] locality is 

 very unusual, as the strata along this portion of the coast ordinarily he in low simple folds. The 

 shale is gray in fresh exposures but becomes more or less oxidized upon exposure. Sandstone 

 dikes, probably derived from interbedded sandstones, cut the shales in the region east of the 

 mouth of the Pysht River, and near Gettysburg hydrogen sulphide gas was noticed escaping 

 from cracks in the shale along the beach. * * * Fossils are abundant and beautifully 

 preserved throughout the finer sediments of the series, at least two distinct horizons being 

 recognized. 



At least five recognizable faunas have so far been found in the Clallam formation. The 

 oldest comes from the lowest clay shales of the series. [For hsts see the work cited.] 



Above the clay shale horizon is a series of medium-bedded to fine massive sandstones in 

 which are found fauna apparently transitional from the clay shales to the coarse sandstones. 



Still a third fauna [Miocene], later than the last, is represented by species found immediately 

 east of Clallam Bay. 



The fourth fauna is that found in sandstone layers interbedded with conglomerates in the 

 upper parts of the formation. 



The fifth fauna of the Ohgocene-Miocene is that found at the mouth of the Sekiu River 

 in beds the equivalent of the uppermost strata of the Cape Flattery section. The relation of 

 this fauna to those [below it] is somewhat problematical, although it appears quite likely 

 that the former is younger than most of the latter. 



Correlations between the diflFerent fossiliferous locahties of the Ohgocene-Miocene series 

 over the whole of the peninsula and Puget Sound region are comparatively easy, as are also 

 correlations with certain of the Oregonian faunas such as those of the Astoria shales and sand- 

 stones, but when it comes to making direct correlations with the Cahfornia or Alaskan faunas 

 much difficulty is encountered. One of the greatest surprises the writer had in aU of his work 

 along the straits was his inabihty to find the characteristic upper Miocene fauna of the Sooke 

 beds which are so well developed only 15 miles to the northward on Vancouver Island. With 

 an almost unbroken series of Miocene faunas one would certainly expect to find the Sooke 

 species somewhere among the lot, but such was not the case and no plausible explanation of 

 their absence has so far presented itself. 



Ir-M 11-12. LAKE BASINS OF WESTERN MONTANA. 



The valleys wliich lie within the mountains of western Montana correspond 

 throughout much of their extent with basins that are partly filled by sediments 

 of IVTiocene and Pliocene age. The deposits were well described by Peale.^^^ They 

 were laid down in lakes, in large part at least, and comprise several t5^es of sedi- 

 ment. The lowest are composed of material derived from the shores of the basins, 

 from pre-Cambrian or Paleozoic rocks. They are succeeded by beds of volcanic ash, 

 in part carried by wind and deposited in the lakes without admixture of foreign 

 material, in part washed in from adjacent land surfaces. The sediments were 

 locally covered by basalt. Peale's description applies to the Bozeman and Madison 

 basins, in which the deposits exceed 2,000 feet in thickness. 



Douglass ^" describes the general distribution of the Tertiary. In a later 

 article ^^^ he distinguished the Sage Creek beds (Eocene?), White River formation 



48011°— 12 53 



