Altitudes between Lake Superior and Rocky mountains, by Warren Upham.
—— Same. No. 73. Washington, 1891. xii, 139pp., 6 pls. .15
CONTENTS.
The viscosity of solids, by Carl Barus.
—— Same. No. 74. Washington, 1891. 119pp. .15
CONTENTS.
The minerals of North Carolina, by Fred'k Augustus Georth.
—— Same. No. 75. Washington, 1891. 173pp. .15
CONTENTS.
Record of North American geology for 1887 to 1889 inclusive, by Nelson Horatio Darton.