U. S. DEPARTMENT OF AGRICULTURE. 
The conspicuous absence of Cretaceous formations in the basin region, excepting in 
the Wasatch Mountains and the Iron Spring district of southern Utah, 1 has been noted 
by many geologists and confirms the conclusion that the basin region was a land mass 
in Cretaceous time. 
The pre-Tertiary was ended and the Tertiary begun by orogenic movement, accom- 
panied by volcanic eruptions. Evidence is not conclusive as to the exact geologic 
division, but opinion seems to predominate that the beginning of the Eocene marked 
the beginning of Tertiary volcanic activity, which extended through the Tertiary 
and into the Quaternary. Following the early volcanic activity of this period, and, 
no doubt, preceded by crustal movements, was the Tertiary lake period (Miocene) — 
King's Pahute Lake. During this period the western half of the basin region was 
occupied by one or more lakes of great extent and irregular outline. Some parts of 
this lake were, no doubt, of great depth, and the lake period was of long duration, 
as is shown by the great thickness of sediments exposed in many places (notable 
examples: Furnace Creek and the Silver Peak quadrangle). The period of lake 
formation was also a period of vulcanism. 
A period of great orogenic movement succeeded the late Tertiary, and during this 
period the basin ranges were formed and the present topography took its main outlines. 
The Miocene lakes disappeared. The late-Tertiary is obscure and has yet to be worked 
out in detail for the region. King was of the opinion that the Miocene lake period 
was succeeded by another lake period, Pliocene, but Russell has shown that, in so far 
as the Pliocene sediments (Humboldt formation) mapped by King are concerned, they 
belong to the Lahontan Lake period. Russell's conclusion is confined to the western 
portion (Map 5, Geological Atlas, Fortieth Parallel Survey) and does not necessarily 
include the eastern half of the basin region. Succeeding the late-Tertiary was a 
period of erosion and continued uplift. The Pleistocene fresh- water lakes were 
formed. The detailed study of these lakes has shown during this time at least two 
periods of flooding and an intermediate desiccation. Fluctuations of the Pleistocene 
lake elevations have been noted also as a conspicuous feature in the history of these 
lakes. Glaciation in the Sierra Nevada and Wasatch Mountains coincide with the 
Eeriod of the Pleistocene lakes. In recent time desiccation of the Pleistocene lakes 
as taken place and minor crustal movements have continued. 
Our inquiry has for its object the study of saline segregates — their nature, occur- 
rence, extent, genesis, and probable commercial utilization. The basin region has 
always been considered a favorable place in which to look for saline deposits. The 
Ere valence of volcanic and eruptive rocks indicates a source from which salines might 
e expected to come. The decomposition of these rocks, the solution of the salts 
resulting, and the fact that this region possesses no outside drainage have caused geolo- 
gists to conclude that saline segregates would be found in manv of the basins. There 
is much evidence, which will be discussed in a later part of this paper, to justify this 
conclusion. 
Turrentine has summarized the geological formations and principal localities in 
which saline segregates have been found. The following table indicates these: 
Geological formations and principal localities in which saline segregates have been, found. 2 
Geologic period. 
Locality. 
Recent . . 
Tertiary. 
Cretaceous 
Jura 
(Keuper 
Trias I Muschelkalk 
|B untersandstein . 
Permian 
Carboniferous 
Devonian 
Upper Silurian 
Kirghiz steppes; Arabia; South America; Dead Sea; Great Salt Lake, 
and numerous other ancient lakes in western United States. 
Cardona, Spain; Wieliczka and Bochnia, Galicia; Siebenbiirgen; Asia 
Minor; Armenia; Rimini, Italy; Petit Anse, La.; California, Utah, and 
Nevada. 
Westphalia brines; Algiers. 
Rodenberg on the Deister; Bex in Canton of Waadt, Switzerland. 
Lorraine; Hall, Tyrol; Hallein and Berchtesgaden (near Salzburg). 
Wurttemberg; in Thuringia, Ernstthall, Stottenheim. 
Hanover, Schoeningen near Brunswick, Salzderhelden; Cheshire, Eng- 
land; Kansas and Texas. 
Gera, Artern (Thuringia); Staasfurt, Halle, Sperenberg; Segeberg (Hol- 
stein); Kirghiz steppes on the River Heck; Kansas. - 
Kanawha and New River, W. Va.; Durham and Bristol, England. 
Winchell,Mich. 
New York; West Virginia; Saginaw, Mich.; Goderich, Canada. 
1 Bui. No. 338, U. S. Geological Survey, Iron Spring District of Southern Utah. 
2 Turrentine, J. W. The Occurrence of Potassium Salts in the Salines of the United States, Bui. No. 
94, Bureau of Soils, U. S. Dept. of Agr., 1913. 
x Ha worth, Geol. Survey, Kansas; Aim. 
Bui., 1S97, p. 56. Harris, La. Geol. Survey, Bui. 7, p. 
