areal and structural geology on the one hand, and the geologists are not
held responsible for paleontology on the other hand. In addition to the
large number of paleontologists on the regular work of the Geological
Survey, as above described, several paleontologists are engaged from time
to time to make special studies.


CHEMISTRY.

There is a chemic laboratory attached to the Survey, with a large corps of
chemists engaged in a great variety of researches relating to the
constitution of waters, minerals, ores, and rocks. A part of the work of
this corps is to study the methods of metamorphism and the paragenesis of
minerals, and in this connection the chemists do work in the field; but to
a large extent they are occupied with the study of the materials collected
by the field geologists. Professor F.W. Clarke is in charge of this
department.


PHYSICAL RESEARCHES.

There is a physical laboratory in the Survey, with a small corps of men
engaged in certain physical researches of prime importance to geologic
philosophy. These researches are experimental, and relate to the effect of
temperatures, pressures, etc., on rocks. This laboratory is under the
charge of the chief chemist.


LITHOLOGY.