REMARKABLE STRATA OT FLINT. 185 



a vaft range of hills running from Dunnofe weft to St. Catha- Geological ac- 



rines. The fubftratum oF theCe hills feem every where to ^J"^'^^^^^'- ^^*» 



be clay lying in ftrata of different colour and purity. The 



loweft is black and very hard ; approaching to (hale. Above 



this fome ftrata have a great mixture of fand, and take the 



appearance of a foft ftone, breaking into very regular cubical 



forms. Thefe ftrata extend over the whole fouthern part of 



the ifland, and terminate againft the chalk range very fuddenly. 



Above the clay ftrata is a bed of ftone in thin layers, and of 



very mingled materials, but in general very hard. Great 



quantities of chert or flint modules appear in this ftone. The 



general thicknefs of the ftratum is from 150 to 200 feet. Above 



this the higheft hills of the range have a ftratum of chalk, 



not pure or white as that of the chalk range properly fo called, 



nor producing flint fo black. 



The height of Dunnofe is 800 feet above low water mark, 

 St. Catharine's hill is at leaft 850. Of the former I had no 

 opportunity of examining accurately the thicknefs of the ftrata, 

 but at St, Catharine's the ftrata are as follow. 



Chalk - 250 feet 



Stone - 200 feet, or perhaps not quite fo much 

 Clay and Sand - 400 feet. 



850. 



This arrangenient accounts entirely for the formation of that 

 fingular coaft called the Underclifl^, which extends from 

 Dunnofe to St. Catharine's ; and is compofed of the confufed 

 fragments of the upper ftratum of rock, which have given way 

 find rolled down, as the fubftratum of clay has been waflied 

 •way by the fea. In moft parts the procefs feems nearly at a 

 ftand ; the coaft being now prote6led by the fallen rocks ; but 

 at St. Catharine's, great devaftation is ftill taking place. The 

 earth-fall mentioned laft year, was a very fmall operation, 

 when compared with the relics of former convulftons. 



From this fliort Iketch of the general pofition of the ftrata 

 in the inland, I return to the particular fubjedl of the prefent 

 paper. 



The chalk pit, which I am about to defcribe is fituated on Defcrlption of ? 



the northern edge of the chalk range juft out of the village of ^^'i^„P'' f^ 

 ^ n 1 f 1 . 1 1 i 1 I . , .. .^ Caiiflbrook, 



Cantbrook, and about an hundred yards beyond the divifion with feams of 



pf the roads to Yarmouth and Shorvvell, The pit is open to ^'"> finguiarly 



' , broken or 

 "le Mattered, 



