Thais, a Palæarctic genus, [42]

Thomson, Sir William, on age of the earth, [213]

Sir Wyville, on organisms in the globigerina-ooze, [89]

analysis of globigerina-ooze, [91]

Thryothorus bewickii, discontinuity of, [68]

"Till" of Scotland, [112]

several distinct formations of, [121]

Tits, distribution of species of, [19]

Torreya, fossil in Spitzbergen, [186]

Tortoises of the Galapagos, [278]