Dr. FiTTON on the Strata below the Chalk. 1 15 



ffood, dicotyledonous. East of Folkstone. Perforated by Gastrochaena ; near Folk- 

 stone. S. Sometimes surrounded with pyrites. Mr. Parkinson states that "fossil 

 " wood occurs plentifully in the marl (gault) of Folkstone ; lying chiefly at the 

 " bottom of the stratum, on the green-sand." Geol. Trans, v. p. 59. 



(15.) Lower Green-sand. — The uniform surface of this stratum, extensively 

 shooting out beyond the chalk, forms a conspicuous feature of the country, 

 which is well seen from the ascent of Folkstone Hill on the road to Dover*. 

 The analogy in this respect to the appearance of the sands at the Black- 

 down Hills in Devonshire, is obvious and striking. The Bagshot sands, above 

 the chalk in Surrey, also exhibit long and uniform platforms, the section of 

 which presents a linear and almost horizontal top, with a rapid escarpment at 

 both extremities. 



(16.) One of the principal circumstances in the internal structure of the 

 Lower Green-sand at Folkstone, is the distinctness with which it is divided into 

 three groups ; and this subdivision probably occurs wherever the formation is 

 fully developed in the South-east of England. It is clearly seen in Surrey; 

 I have evidence from Mr. Martin of its existence in the West of Sussex ; 

 Mr. Lonsdale believes it to hold also near Devizes in Wiltshire ; and though I 

 did not become acquainted with it till after I had examined the Isle of Wight, 

 I have little doubt that it will be found there also. 



a. The first of these subdivisions may be characterized as consisting prin- 

 cipally of sand, white, yellowish, or ferruginous, with concretions of limestone 

 and of chert, frequently in false stratification. It forms commonly a flat, but 

 sometimes an irregular hilly surface, rising from the valley of the gault, and 

 bearing a dry, barren soil. 



b. The second member abounds in green matter, is retentive of moisture, 

 and contains comparatively little stone : it occupies a flat and marshy tract, 

 between the first and third divisions. 



c. The third and lowest member contains a greater proportion of calca- 

 reous matter, and includes some of the principal beds of stone bearing the 

 name of " Kentish Rag" ; which commonly form a prominent ridge at its 

 outcrop, adjoining the valley of the Wealdf . 



* From Folkstone Hill the ridge of Fairlight Down, near Hastings, is a very striking object : 

 its range is evidently parallel to that of the chalk outcrop, as might be expected in the axis of 

 elevation of the tract by which it is surrounded. 



■j- In Mr. William Smith's Geological Map of Kent, two ranges are indicated, by darker co- 

 lours, in the tract between the coast and Maidstone ; one running parallel to the chalk, from 

 Sandgate through Ashford and Bursted to Penenden-Heath, on the N.E. of Maidstone ; the lower, 

 less regularly, from Hythe along the verge of the Weald Clay. These bnes, I have no doubt, indi- 

 cate a subdivision like that mentioned in the text : but in the explanatory table of the map, the 

 stone of the tract thus coloured is said to be the Portland-rock. 



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