Stopping power of substances with reference to alpha rays, 219.

Struggle for existence, dynamic basis of, 80.

Strutt, Prof. the Hon. R. J., age of geological periods, 20;
radioactivity of zircon, 223.

Sub-Apennine series of Italy, 148.

Suess, nature of earthquakes. 143.

Survival of the fittest and the organic law, 80.

T.

Talchir boulder-bed, 136.

Temperature gradient in Earth's crust, 126.

Termier, section of the Pelvoux Massif, 254.