probable origin from shale, [144];

ropy, [113];

viscosity of siliceous, [103].

Lava domes, probable structure of walls of, [112];

slopes of, [103], [104], [105].

Lava projectiles, pear-shaped type, [121].

Lava reservoirs, formation of, [143].

Lava streams, appearance of, [133], [134].

Lava surface, [113], [124].

Law of the desert, [197].