Thorium, a new metal, xvii, 381.
Thorn fence, x, 167.
Thracia, see [Zoology, Mollusca.]
Thrombolite, xlii, 386.
Thunder storms, see under [Wind.]
Thury, H. de, on springs and fountains, xviii, 267.f
Thylacotherium, xxxvii, 228.
Tiarks, J. L., on the northern boundary of the Lake of the Woods, xv, 41.
Ticknor, G., letter to, from Baron von Waltershausen, xlvii, 100.
Ticonderoga, walls of, iv, 49.