20

THE CHALK RANGE.

pit. Besides the beds of flints which separate the strata, detachednodules are also found scattered sparingly through the most solidparts of the beds ; and sometimes flint may be seen in a thirdstate ; namely, filling, in thin sheets of very considerable extent,the fissures which run through many of the strata, cutting themin general at nearly right angles to the plane of the strata.These fissures are seldom above two inches wide, and the plateof flint which fills them, seems to have been formed from each sidetowards the centre, which often contains some loose, calcareouspowder inclosed between the two silicious plates. The flints arenot in general quite so black as those of other chalk strata, butfull as finegrained and pellucid, except where they are debasedby iron, which not unfrequently happens ; and sometimes theiron is in such quantity as to cause the flints to decompose rapidlyon exposure to the air. Pyrites are not unfrequently found inthe chalk in nearly spherical nodules radiated to the centre.

All the flints above described, except those detached nodulesin the body of the strata, are universally found in a most ex-traordinary state : they are broken in every direction into piecesof every size, from three inches diameter down to an absolutelyimpalpable powder. The flints thus shivered, as if by a blowof inconceivable force, retain their complete form and positionin their bed. The chalk closely invests them on every side, andtill removed, nothing different from other flints can be perceived,excepting fine lines indicating the fracture, as in a broken glass ;but when moved they fall at once to pieces. The fragmentsare all as sharp as possible, and quite irregular, being certainlynot the effect of any peculiar crystallization or internal arrange-ment of the materials, but merely to external violence. This