show the distribution of land and water during a number of 
stages following the glacial period. 
Hall 36: Petroleum, Coal, Clays and Sands. — The east 
end of this hall is occupied by the petroleum exhibits, be- 
ginning with oil sands of the American oil fields, followed 
by crude petroleums grouped geographically. The derivatives 
of petroleum, and specimens illustrating their uses, form 
another large collection. A model of the original Rockefeller 
refinery at Cleveland should be inspected. Near the center 
of the hall is the coal collection which is arranged according 
to kind and geography. Following is a collection of coal 
products, such as tars, antiseptics and dyes. 
The west end of the hall is occupied by exhibits of clays, 
soils, sands, and other earthy materials. Two cases contain 
specimens which show how soil is formed, of what it is com- 
posed, the plant foods it contains and the nature of the sev- 
eral kinds of soils, such as loams and marls, which are or- 
dinarily recognized by farmers. Another case contains soils 
grouped according to the more exact classification of the 
U. S. Department of Agriculture. This is followed by a col- 
lection of numerous soils arranged according to kind. In 
the large clay collection, the clays are arranged according 
to kind. A smaller group of clays occupies four cases, and 
illustrates the numerous kinds of clay, and the relation of 
these kinds to each other. As most clays are used in the 
form of brick, tile pottery or other burned ware, there ap- 
pears with most of the specimens a little brick burned from 
the specimen itself. Other minerals of industrial importance 
represented are sands, fullers earth, cement rocks, mineral 
soaps, silicas and earthy pigments. Against the west wall 
is a model of the Chandler Iron Mine. 
Near the center of the hall, asphalts, oil shales and graph- 
ites are exhibited, which contain, not only examples of the 
materials as mined, but also specimens illustrating their 
uses. A case in the center aisle contains diamonds, the rocks 
in which they are found, and minerals associated with them. 
Two cases contain peat and objects made from peat. The 
mode of formation of peat is illustrated by a model of a 
lake in which peat is forming. 
Hall 37: Frederick J. V. Skiff Hall. Ores, Marbles and 
Alkalies The east half of the hall is occupied by a collec- 
tion of ores of the precious and base metals. The metals are 
arranged separately, the ores of each metal forming a sep- 
arate group, except in the case of gold, silver and lead, which 
are shown together. The ores of each metal are arranged 
in geographical order according to country, state and min- 
ing district from which they are obtained. With the ores, 
are displayed a number of models which illustrate methods 
of mining and treatment. Smaller groups of specimens illus- 
trate the uses of several of the metals and their compounds. 
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