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structure of the districts represented. Each color represents a 
geological formation, and shows the area over which it is known 
to be the surface rock beneath the covering of sand, gravel, clay, 
&c. The large relief map of New Hampshire in the first alcove 
on the east side is also colored geologically, so as to represent 
the geology of the State. The series of maps of the eastern part 
of North America also show approximately the extent of land 
above the sea at the close of the geological period last added, and 
consequently the geography of that time. The series when taken 
together also shows the gradual increase of the continent during 
the successive periods. 
COLLECTION OF BUILDING AND ORNAMENTAL 
STONES. 
There is a collection of American building stones arranged in 
cases in the hallway of the lower floor of the new building, at 
the foot of the main stairway. It contains 1,050 blocks princi- 
pally four inch cubes, polished on the face, and variously dressed 
on the other sides. The specimens represent nearly every State 
in the Union, and contains samples of all grades of Granite, Sand- 
stone, Limestone, Marbles, Slates and other rocks used for build- 
ing and ornamental or monumental purposes. Each of these 
samples is accompanied by a label giving the name of the quarry, 
that of the person or company working it, the location, name of 
the material and the geological position. The collection is at 
present arranged geographically under the different States, and 
each specimen is numbered and catalogued, and may be consulted 
and examined by interested persons on application to the Curator 
of Geology. This collection is a duplicate of that used by the 
experts employed on this department for the " Tenth Census 
Report," and has been made at great expense by Mr. Morris K. 
Jesup. There is also a slide prepared for microscopic study 
belonging to each block in possession of the Museum, many of 
which were reported on in the "Tenth Census Report." The cata- 
logue of this collection has been published in the magazine 
"Stone," published at Indianapolis, Ind., devoted to the interest 
of stone quarrying and working. Vol. 1, No. 7 Nov.. 1888. 
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