DEPARTMENT OE GEOLOGY 48 
Japan is represented by polished marble spheres of various 
sizes. 
A series of marbles from Africa and Asia includes the well 
known ivory-colored Numidian marbles. 
A series of travertines including some large polished speci- 
mens comprises the varieties commonly known as Mexican onyx, 
onyx marble and stalagmite marble. The clear translucent 
specimens represent the material as originally deposited. The 
opaque red-brown effects are produced where air has had long 
access to the material in the ground and has caused an oxida- 
tion of the iron contained in the stone. 
The green and red serpentines or serpentine marbles, which 
after the true marbles are the most generally used of the orna- 
mental stones, are abundantly represented. 
Especially noteworthy are the curiously mottled red and dark 
green serpentines from Lizard Point, Cornwall, and the dark 
colored variety from Saxony which is turned on a lathe to form 
various ornamental objects. All of these green serpentines are 
now commonly known as verde antique, although the name was 
formerly applied only to those of the shade of green possessed 
by the Greek specimen, E 504. The ophite from New York is 
a granular mixture of calcite and serpentine. 
A number of polished slabs of granite and eruptive rocks are 
shown. Owing to their hardness and the consequent expense of 
working, these stones are not so frequently polished as the 
marbles, but, as illustrated by these specimens, when polished 
they often present very beautiful effects. 
A systematic collection of common building stones is exhib- 
ited in the form of four-inch cubes showing different kinds of 
finish on different faces. The series is classified according to 
the commercial groups of limestones, marbles, sandstones and 
granites, and in the nearest of these classes are placed such 
l)uilding stones as lava, diorite, conglomerate, etc., which do not 
strictly belong to either. 
Hall 68. 
CLAYS, SANDS, AND SOILS 
The arrangement of cases in this hall divides it into two 
alcoves on either side of a central passage. The space to the 
