UNITED STATES GEOLOGICAL SURVEY

CHARLES D. WALCOTT, DIRECTOR

SURVEY

OF THE

BOUNDARY LINE BETWEEN IDAHO AND MONTANA

FROM

THE INTERNATIONAL BOUNDARY TO THE CREST
OF THE BITTERROOT MOUNTAINS

Letter of transmittal

Instructions...

Boundary lines..

CONTENTS.

Account of operations

Latitude, longitude, base line, azimuth, and triangulation.

Latitude

Longitude.

Spokane base line.

Azimuth

Triangulation

Transit and stadia work

Monuments

The international boundary west of the summit of the Rocky Mountains,

and the Mooyie Trail monument

Financial statement

Index

5

ILLUSTRATIONS.

Page.

PLATE I. Crest of Bitterroot Mountains...........

16

II. A, Cabinet Range; B, Summit of Cabinet Range, showing points
touched by boundary line.

18

III. A, Camp south of summit of Cabinet Range; B, Quartzite slate
near summit of Scotchman Peak.

IV. Astronomic piers in court-house grounds at Spokane, Washington.
V. Diagram of triangulation for control of the Idaho-Montana
boundary....

2220

VI. Transit station on random line.

VII. Granite boundary-line monuments

VIII. Design for iron post....

IX. Post 48, at summit of timbered ridge.

X. Post 42, and line cut through timber

XI. A, Granite monument on boundary line near Leonia, Idaho; B,
sectional monument at summit of Bitterroot Mountains..

54

XII. Clark Fork of Columbia River just west of boundary line..
XIII. Summit of Bitterroot Mountains, showing pack train loaded with
sections of granite monument..

56

XIV. Map of boundary line.

FIG. 1. Design for stadia rod..