Successive flexures or ridges are ranged in more or less parallel lines, and from between the bands of hard, unyielding rock of older formation the soft beds of recent shale have been washed out, to he carried through the enclosing ridges by rifts which break across their axes.
Shales occur, and the passage of the streams through deep rifts or gorges across the hard limestone anticlinals, which stand in irregular series of parallel ridges with the eroded valleys between.
The intellect is a cleaver; it discerns and rifts its way into the secret of things.
Pinnacle on the western side, contains a low new cone with numerous steaming rifts and vents.
An outbreak in 1894 produced numerous rifts in the inner walls from which steam and smoke have issued ever since.
This confined sea-water is gradually being displaced by the downward sinking of the rain-water through the rifts of the strata, and thus finds its way to the surface: so that these springs offer to us a share of the ancient seas, in which perhaps a hundred million of years ago the rocks of Kentucky were laid down."
Barnard's photographs of its structure leave little doubt on the matter; the numerous rifts and dark openings show that its thickness cannot be very great.
The last phase of vulcanicity took place along the great meridional rifts of East Africa, and though feebly manifested has not entirely passed away.
Nevertheless the Milky Way contains a fair proportion of lucid stars, for these are considerably more numerous in the bright patches of the Milky Way than in the rifts and dark spaces.
Whilst northern Africa was being folded, the East African plateau was broken up by a series of longitudinal rifts extending from Nyasaland to Egypt.