Organic sediments, [34].

Orgeln, [182].

Orleans, Duc d’, cited, [286].

Orographic blocks, [58].

Osar, [311], [315], [316].

Oscillations of movement, on coasts, [253].

Outcrop blocks, for study of maps, [63].

Outcroppings, [46].

Outlets, from continental glaciers, [271];

of glacial lakes, [326], [327].