CHALK. 49 



which is in the same quarter. Similar undulations in the chalk beds 

 may be observed in Lincolnshire, and in the southern counties. 



Chalk is a calcareous rock so generally known, that it is unne- 

 cessary to give a minute description of it. Yet it will be proper to 

 make some observations on the structure of a bed which holds such 

 an important station in our district; especially as our remarks may 

 assist some of our readers in comparing the chalk of Yorkshire with 

 that of other places. 



In examining the chalk, in the quarries on the Wolds, and in the 

 cliffs of Flamborough, we see the upper part of the bed not present- 

 ing a smooth surface, but broken and shattered, and intermixed with 

 the alluvial soil, which is generally very thin. It is intersected by 

 numerous fissures or seams, both parallel to the general bed, and 

 perpendicular to it ; so that it is easily divided into angular fragments. 

 As we proceed downwards, the parallel seams, which constitute the 

 chalk a stratified rock, become less numerous, so that the strata grow 

 thicker and thicker; and as the perpendicular fissures, which are less 

 Tegular than the seams of the strata, also diminish in number, the 

 middle and lower parts of the great chalk bed are much more com- 

 pact than the upper part. Indeed, as the broken chalk descends but 

 a short way from the top, the great body of the chalk, but especially 

 the lower part, has a massive appearance, with very few horizontal 

 partings: and as it has a tendency to split in a perpendicular direc- 

 tion, in preference to a horizontal fracture, the chalk cliffs on both 

 sides of Flamborough Head, and at the Head itself, have a beautiful 

 columnar aspect. For the same reason, numerous recesses and . 

 caverns, some of them highly romantic, occur in these cliffs; parti- 

 cularly towards the extremity of the Head, where the waves of the 

 German Ocean, beating with great force into the lower part of the 

 perpendicular fissures, has hollowed them out into curious grottos 

 and niches, and sometimes extensive caves, while the more solid 



N 



