The organization, as at present established, executing this work, is as follows:  First, an astronomic and computing division, the officers of which are engaged in determining the geographic coordinates of certain primary points.  Second, a triangulation corps engaged in extending a system of triangulation over various portions of the country from measured base-lines.  Third, a topographic corps, organized into twenty-seven parties, scattered over various portions of the United States.  Such, in brief outline, is the plan for the map of the United States, and the organization by which it is to be made.  Mr. Henry Gannett is the Chief Geographer.

PALEONTOLOGY.

Before giving the outline of the plan for the general geologic survey, it will be better to explain the accessory plans and organizations.  There are in the Survey, as at present organized, the following paleontologic laboratories: 

1.  A laboratory of vertebrate paleontology for formations other than the Quaternary.  In connection with this laboratory there is a corps of paleontologists.  Professor O.C.  Marsh is in charge.

2.  There is a laboratory of invertebrate paleontology of Quaternary age, with a corps of paleontologists, Mr. Wm. H. Dall being in charge.

3.  There is a laboratory of invertebrate paleontology of Cenozoic and Mesozoic age, with a corps of paleontologists.  Dr. C.A.  White is in charge.

4.  There is a laboratory of invertebrate paleontology of Paleozoic age, with a corps of paleontologists.  Mr. C.D.  Walcott is in charge.

5.  There is a laboratory of fossil botany, with a corps of paleobotanists, Mr. Lester F. Ward being in charge.

The paleontologists and paleobotanists connected with the laboratories above described, study and discuss in reports the fossils collected by the general geologists in the field.  They also supplement the work of the field geologists by making special collections in important districts and at critical horizons; but the paleontologists are not held responsible for 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.