892 HISTORICAL GEOLOGY. 



group, of Safford (1864), the Appomattox of McGee (1888), — all of one formation, and 

 now named by agreement the Lafayette ; made by Hilgard, and in this work, a formation 

 of the Glacial period. Marine deposits of this period are well developed along the Caloosa^ 

 hatchie Eiver, south Florida. To the north, considerable areas are supposed to have been 

 occupied by lakes having but slight elevations, and subject to occasional intrusions of 

 the sea with its salt-water fauna ; hence the Peace Creek bone beds in Manatee County, 

 and Alachua clays, in Alachua County, are found apparently interstratified with marine 

 Pliocene deposits (Dall, TJ. S. G. S. Bulletin, No. 84). The Mammals include a considerable 

 number of Eocene, Quaternary, and Pliocene species, and the beds are supposed to be 

 Quaternary in accumulation. 



Dall reports that the Miocene group of Gay Head, Martha's Vineyard, is overlaid by 

 beds affording Pliocene fossils (1894). 



MiocEXE AND Pliocene of the Pacific Coast. — Along Carrizo Creek, east of the 

 coastal range of mountains in southern California, there is a bank or terrace, sometimes 

 composed of fossil shells in its upper part, that has been referred to the Miocene Tertiary 

 by Conrad and to the Pliocene by Gabb. The sandstones and shales of the Santa Suzanna, 

 Santa Monica, and Santa Inez ranges are mainly referable to the Miocene ; the conglomer- 

 ates and sandstones about the base of the San Gabriel range can only be classed as Neocene. 

 Resting on the granitic axis of Santa Lucia Mountains are highly metamorphosed Neocene 

 (Miocene ?) sandstones ; stratigraphically above are thick deposits of bituminous shales, 

 which toward the southeast are overlaid by soft, sometimes calcareous, sandstone, having 

 a thickness of over 1000', and referable to the Miocene series on paleontological evidence. 

 Sandstones and bituminous slates of this age have been described from the Sierra de 

 Salina, Gavilian, Santa Cruz, and Mount Diablo ranges. In the region of Mount Diablo 

 Turner finds the Miocene series made up of coarse gray sandstone containing the 

 large Ostrea titan, and conglomerates with pebbles of rhyolyte, quartz, and metamorphic 

 rock. The Pliocene beds contain marine fossils, silicified wood, hornblende-andesyte tufa, 

 and pebbles. North of the Golden Gate several fossiliferous Miocene deposits have been 

 recorded, but their characters and limits are unknown. Along the foothills of the Sierra 

 Nevada, especially in the vicinity of Ocoya Creek, there are Miocene beds of fine sand, 

 coarse sand, conglomerates, fragments of pumicestone, ferruginous fossiliferous gravel, 

 and clay nodules, in all 160' thick. Farther to the north, the lone formation of Lindgren, 

 best developed in Amador and Calaveras counties, is composed of (1) 100' of clay rock, 

 (2) 100' of sandstone, (3) 860' or more of white clay and sand beds containing coal seams. 



In Oregon, Miocene sandstones and shales occur at Astoria, and others, presumably 

 of the same age, at Port Orford, Cape Blanco, and near Yaquina Bay. They are perhaps 

 a continuation of the bituminous shales and sandstones of California. From 1 to 3 miles 

 east of Eugene City, Dall has noted a Miocene sandstone 37' thick. Condon states that 

 the backbone of the Coast Range consists of argillaceous Miocene shale similar to that at 

 Astoria ; stratigraphically above are the fossiliferous Solen beds of Condon, also of 

 Miocene age ; on the flanks of the highlands there are lacustrine deposits containing some 

 Equus bed (Quaternary) fossils. 



In. Washington, the Astoria clay-shales are reported from near Bruceport, and at vari- 

 ous points on Shoalwater Bay. Other outcrops of the same formation are known from 

 Vancouver Islands and Alaska. 



The Pliocene Merced group of Lawson {Bull. Geol. Univ. Gal., i., 142, 1893), on the 

 coast of the San Francisco peninsula, south of the Golden Gate, is described as having a 

 thickness of 5834'. A cliff consisting of the beds, 720' high, extends from Lake Merced, 

 near San Francisco, to Mussel Rock, about 8 miles south of Point Lobos. The basal bed 

 contains some carbonized wood and leaves. Some of the fossils were described by J. G. 

 Cooper in 1888, and a list of others, determined by Dall, is given in Lawson's paper. 

 Delta material in the great valley of California at San Benito also is referred by him 

 to the Pliocene. 



