244 REMARKABLE STRATA OF FLINT. 



Obfervations on flints in it. The ftratified flints in this pit are full as much 

 ftrTta'of fUnt ^^^^^6^^^ ^s any I had feen. The nodules are not at all broken, 

 in the Ifle of Many of the ftratified flints are much defaced in this pit by an 

 Wight. admixture of pyrites, fo as to be quite opaque like a coarfe 



jafper, and thefe flints are much fofter than the others^ as is al- 

 ways the cafe in the impure flints. 



In the chalk pits near Carift)rook the ftrata are not fo vifible 

 as in the pits north of the c.aftle (defcribed in the firft papers) 

 but the flints are to the full as finely, though perhaps not fo 

 generally broken. In one flint I obferved that though it lay in 

 its bed undifturbed, chalk as if in a fluid ftate had run into one 

 of the fifl'ures. Every appearance of this pit indicates that the 

 chalk, fince its (Gratification, has received a moft violent fliock. 

 The chalk at Freftiwater bay appears in high perpendicular 

 clifl?*s, particularly on the weflern fide of the bay. Both on the 

 eafl:and welt the ftrata dip northward near 80 degrees, and the 

 dip feems to run eaft and weft very regularly. The weftern 

 clitf has a very regular and perpendicular face to the eaft ward ; 

 and here the parallel direction of the ftrata, each feparated by 

 a thin line of black flint prefents a moft curious appearance. 

 The flint here is often found in thin plates of confiderable ex- 

 tent, fometimes not above an inch thick, and feems formed 

 from each fide of the fpace which it fills, as the exterior parts 

 (or tliofe neareft the chalk) are the pureft and blackeft, and it is 

 gradually whiter towards the middle, where there is often a 

 foft line of chalk included between the two plates of flint. All 

 the ftratified flints are more or lefs fliattered, and fome are re- 

 duced to very fine powder. The cave at Frefliwater, which 

 is really a beautiful as well as a very curious one, is formed by 

 the adionof the fea on thefe nearly vertical ftrata. They are 

 of different hardnefs, 2«id all interfecled with filTures at right 

 angles to the ftrata. When the fea ads on and wears away a 

 foft ftratum, a gallery is formed, and the upper parts of the ftra- 

 tum between fiflure and fiflure drop out, much in the fame way 

 as bricks are apt to do out of the flat arch over a window, the 

 harder contiguous ftrata ferve as walls to the gallery, but are by 

 degrees perforated in different parts, and become irregular pil- 

 lars, fupporting the vaft weight of the hills above, until the 

 a6tion of the fea weakens them fo far that they fall, and a part 

 of the face of the hill goes witli them, fo that the cave is con- 

 flantly, although flowly, changing its form. 



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