DEPARTMENT OF GEOLOGY 
Hall 34: Minerals, Crystals, Meteorites, Physical Geology. 
— The east half of the hall is occupied by the mineral col- 
lection, in which the minerals are arranged in the customary 
order. The collection begins at the east end of the hall with 
the native elements and ends with the hydrocarbons. The 
William J. Chalmers crystal collection follows. This collec- 
tion illustrates, by means of carefully selected mineral spec- 
imens, the systems according to which minerals crystallize, 
and the varying development of crystal form in each system. 
Several types of twin crystals, and the laws of crystal 
grouping are illustrated, as well as various other features of 
crystal growth, such as zone structure, inclusions and phan- 
toms. 
An extensive meteorite collection occupies the larger 
portion of the western half of the hall. This collection con- 
tains specimens of the great majority of the known meteor- 
ites, arranged according to the established classification. 
Many of the specimens are in the form of polished and 
etched slabs, which display the interesting interior structure 
of meteorites. The exterior features peculiar to these bodies 
are shown by numerous complete and unbroken meteorites. 
Four of these, installed in separate cases, each weigh from 
466 pounds to nearly two tons. 
The west end of the hall is occupied by a part of the 
collection of physical geology which illustrates glacial phen- 
omena, rock weathering and concretions. Two large rock 
slabs, displayed on bases in alcoves near by, show the effects 
in unusual perfection of glacial planing and grooving of rock. 
The rest of the physical geology collection is installed in 
Hall 35. 
Hall 35: Physical Geology, Rocks, Relief Maps. — The col- 
lections at the east end of this hall are a continuation of 
those in the west end of Hall 34. The more important groups 
are those illustrating volcanic products, dendrites, tufas, 
veins and vein structure, faults, folds, joints and cave forma- 
tions. A large case contains a cave rebuilt from selenite 
crystals from the original cave. A large fulgurite occupies 
another case. A model of the Natural Bridge of Virginia 
is placed in the aisle. Near the center of the hall a large 
collection of rocks fills eight cases. 
More than half of the hall is occupied by a collection 
of relief maps, which show the topography of selected por- 
tions of the earth^s surface. Some of these are representa- 
tions of well known scenic areas. Others illustrate the 
topography of States and other political divisions. Portions 
of the earth’s surface, which are of unusual geological in- 
terest, are also presented in relief. Of local interest are 
a group of relief maps of the region around Chicago, which 
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