LATER TERTIARY (MIOCENE AND PLIOCENE). 825 



present sufficient to determine the extent of the Payette Lake, though it is probable that it 

 was confined to the Snake River valley, inclosed on the west by the Blue Mountains and on the 

 east by the divide toward the Salmon River. 



In a subsequent study Lindgren extended the observations on the Payette 

 (Eocene?) and overlying Idaho (Pliocene) formation in the Snake Canyon region. 

 Details of occurrence and notes on the fauna by Dall and flora by Knowlton are 

 given in his report.^^® 



Russell ^^* gives the following sketch of the Payette formation in Oregon: 



The Payette formation, which consists principally of unconsolidated sands, clays, gravel, 

 etc., together with important beds of light-colored and frequently white volcanic dust, and 

 which is widely exposed in southwest Idaho, extends westward into Malheur County, Oreg., 

 where it forms a large portion of the surface. This formation was crossed during my recon- 

 naissance in 1902 and again in 1903, but its entire extent in Malheur County can not as yet be 

 stated. It occupies the Snake River valley, from near Owyhee northward beyond Ontario, 

 and extends westward to a locality about 30 miles southwest of Vale. Similar beds occur also 

 along the courses of Jordan and Succor creeks and in several other valleys. As exploration 

 progresses it will probably be found that many of the valleys of Malheur County are floored 

 to a depth of several hundred feet with soft unconsolidated deposits like those of the Payette 

 formation and probably of the same or of approximately the same age. Whether all of these 

 deposits are portions of one continuous formation, or were laid down in separate and contiguous 

 basins, is not as yet determined. It is probable, however, that they were accumulated in much 

 the same manner that beds of like character are now being spread out on the surface of the 

 valleys of the same region by existing streams. In most of the sediments referred to as being 

 analogous to the Payette formation, however, volcanic dust added materially to the depth of 

 the deposits. 



L 10. COAST RANGE OF OBEGON. 



Diller ^^^* says : 



The Miocene is widely distributed in western Oregon on both sides of the Coast Range. 

 It occurs over a large part of the WUlamette Valley * * * ^nd on the coast more or less 

 continuously from Astoria to Coos Bay, and most likely beyond, with interruptions, to California. 



Descriptions of local observations and identifications of fossils by DaH follow 

 this general statement. A type section of the Miocene is exposed near Empire City, 

 Oreg., from which the Empire formation takes its name. Diller -''° states that the 

 Empire formation consists chiefly of sandstones and dark shales below with white 

 shales above, in all not more than 500 feet thick at the type locality. 



Dall ^" classifles the Empire formation in relation to the Astoria group as 

 follows : 



Empire heds. — From typical exposures near Empire City, Coos Bay, Oregon. * * * 

 These beds are well exposed between Pigeon Poiat and FossU Point, 3 miles southwest of Empire 

 City, and abut unconformably upon the Oligocene beds at Coos Head and the Eocene at Marsh- 

 field, in the same region. At Fossil Point they are overlain by the richly fossUiferous Pleistocene 

 beds of the Coos conglomerate. So far as can be judged from the fauna collected, the Empire 

 beds are the exact equivalent of the upper part of the Miocene beds at Astoria, caUed by Dall, 

 in 1892, the Astoria sandstones, to distinguish them from the (Oligocene?) Astoria shales 

 (formerly called Miocene), which conformably underlie them. The exact place of the Astoria 

 shales in the colunm must await a better knowledge of the fauna. If the double use of the name 



