GRAVESEND. 425 



Neither are the perpendicular fissures of the same 

 description throughout, for sometimes they go in a 

 straight line right up the wall. Sometimes when they 

 have gone a certain distance, they stand obliquely, and 

 then another begins a little on either side, and runs up in 

 a straight line. The width of such a fissure behaves in the 

 same way, as has been said of the horizontal ones. The 

 distance between the perpendicular fissures, as with the 

 horizontal ones, is not uniform, but sometimes wide, 

 sometimes narrow, often only i inch and even less ; but 

 sometimes 2, 4, 6, 8, and 10 feet wide. 



[T. II. p. 73]. These perpendicular fissures, or 

 'joints,' commonly preserved a certain direction, for they 

 mostly ran from E. to W. and from N. to S., or about, 

 it might be, a slight curve from W. to N. and E. to S., as 

 well as from S. to W., and from N. to E. But this was 

 so slight, that it could scarcely be noticed. Yet there 

 were at times some seen which departed from this rule, and 

 ran for example from S.E, to N.W., from N.E. to S.W., 

 and so on. Nevertheless, this curvature happened seldom 

 enough. They commonly lay, as was first noted, and this 

 in chalk pits, which were a whole English mile from each 

 other. 



When pieces of chalk were drawn out of the rock, 

 their sides facing the perpendicular fissures were quite 

 plane, and as smooth as if they had been cut even with a 

 knife drawn along a rule- 



The chalk walls which have been longer exposed, 

 and on which both the sun, air, and rain have operated 

 longer, are far more full of perpendicular, horizontal and 

 oblique fissures, than that which is newly quarried. At 

 . least the former could be more plainly seen : for an old 

 chalk, which has been longer exposed, is nearly cracked 

 all to pieces, while in a newly fractured surface one can 

 with difficulty see any cracks. 



