GEOLOGY OF FOLKESTONE — THE GAULT. 



85 



and ever and anon brick- works and tile-kilns, like sigTial posts, stand 

 out upon its tract. All round the dialk-hills, in their extended semi- 

 circle-range, and again on the shores of the Gallic lands across the 

 " narrow straits," through Dorsetshire, through Cambridgeshire, 

 ever cut off from the white chalk hills by a green sandy belt (the 

 Upper Greensand), sometimes developed into thick courses of sand 

 and firestone, as in Surrey and the Isle of Wight, sometimes only a 

 naiTow dark gTeen bed measuiTible in inches, as in Eastwear Bay, 

 and cut off from the beds below — the Lower Greensand and Neoco- 

 mian — by a stratum still more remarkable in its characters, value, 

 and origin. 



Lign, 9. — Ammonites inten'uptus. From the " Ammonite-stratum" of the Gault. 



Near the base of the Gault there streams along a single narrow 

 layer of broken casts of lai'gish ammonites.* Once measuring the 

 distance from the basement-bed above referred to, or, as for years I 

 have rather called it, the "junction-bed," with the handle of your 

 pick, or any other ready means, strike where you will along the en- 

 crusted, or debris-covered face of the cliff, there surely will your pick's 

 point clatter against those hard and rugged nodules. There they 



* These casts are cliiefly those of Ammonites Benetianus^ with a smaller pro- 

 portion of A. interru^tus. 



