GREENSAND OF ATHERFIELD CLIFFS. 225 



after heavy gales and high tides, which sweep 

 away both the fallen masses of rock and the sea- 

 beach, and expose a large surface of the ad- 

 jacent strata washed clean, and visible at low 



water.* 



1. Lowest Greensand clay.f — A bed of brown clay with 

 marine shells : 3 feet thick. In the lowermost layers, 

 near the Wealden shale and clay, are seams of minute fish- 

 bones. 



2. Perna Mulleti band. — A stratum two feet thick, of a very 

 firm sand-rock, characterised by numerous shells, and 

 especially by a layer of the Perna Mulleti (PL IV. fig. 

 6) ; which also occurs in the same relative stratigraphical 

 position in Compton and Sandown Bays. 



3. Lower Lobster clay-bed. — Clay strata, with numerous fos- 

 sils in the lower, and but few in the middle beds. The 

 upper layers are remarkable for the abundance of a small 

 species of lobster (Astacus), which occurs in a beautiful 

 state of perfection, imbedded in blue saponaceous clay ap- 

 proaching to fuller's earth. The specimen figured in the 

 Vignette of the title-page of this work, is from this stratum. 

 Total thickness 100 feet. 



4. The Cracker's rock.% — Sandy clay with two bands of 

 nodular or concretionary masses of very hard calciferous 

 sandstone : 18 feet. These beds are highly interesting for 

 the abundance and variety of their organic remains. The 

 nodules consist of very compact rock, and contain innu" 

 merable shells in a perfect state, of which many species 



* Such was the state of the cliff when visited by Dr. Fitton in 1843. 

 Proc. Genl. Sue. vol. iv. part 1. 



t The names adopted are those employed by Captain Ibbetson and Pro- 

 fessor E. Forbes. Gcol. Journal, vol. i. p. J90. 



I This local name is said to be derived from the noise made by the breakers 

 when dashing over the rocks and ledges of this concretionary sand-rock. 



