Fracture control, of drainage lines, [224].

Fracture, experiments on, [41];

of minerals, [450];

zone of, [40], [46].

Fractures, in rocks, shown by rectilinear lines on map, [65];

system of, [55].

Free, E. E., cited, [222].

Free waves, [232].

Fretted upland, [372], [373].

Frost, prying work of, [152].