Dr. PiTTON on the Strata below the Chalk. 155 



chalk : a fact which is the more deserving of attention^ as several other genera 

 and species are found both in the Upper green-sand and the Lower chalk*. 



(72.) Vicinitj/ of Pulhorough. — I am indebted to Mr. Martin for the section 

 (Plate X a. No. 5.) across the Wealden district, from Duncton Beacon on the 

 South Downs, through Petworth, to Cranley; and I have, from my own ob- 

 servations, continued it in the same direction to the North Downs. This 

 section shows, what Mr. Martin's recent observations have fully confirmed, 

 that the subdivisions of the sands below the chalk, in the north-west of Sussex, 

 correspond with those above described, in the neighbourhood of Folkstone ; 

 and that a similar valley distinctly marks, in both cases, the place of the middle 

 greener and retentive sands, (24.). I have had myself also an opportunity of 

 seeing, with Mr. Martin, a section parallel to that of Plate X a., in which this 

 structure is very clearly displayed, on a line about half a mile west of Pul- 

 borough, passing through the heights of Park-hill farm and Pethenden (with 

 the valley of the middle sands between), to a detached summit within the 

 Weald-clay, called Pickhurst Hill ; (See Plate X b. fig. 2.). Fuller's-earth 

 like that of Nutfield, appears at Fittleworth Church, near Pulborough. 



Besides the mass of this intermediate group, a detached stratum, about 40 feet in thickness, of 

 dark-coloured, greenish grey, retentive sand, including much pyritous matter, occurs above it, 

 with some feet of ferruginous and yellowish sand between ; — a subordinate bed, in fact, within the 

 upper ferruginous mass of the sand : and this ought to be held in view, as in some cases it might 

 be mistaken for the Gault. It is very conspicuous on the ascent of the London road, from the flats 

 on the south, to the church at Pulborough ; and can be traced thence, almost continuously, for 

 some miles both to the east and west. No fossils have been found in this stratum, except some 

 impressions of what may be the branches of fuci. A bed of dark hue, with the same characters, 

 seems to occupy a corresponding place in the series near Reigate : See note \ on (52.). 



(73.) This country has been the scene of several upheavings and derange- 

 ments of the strata, analogous to those above mentioned in West Kent (41. 

 to 43.), but much more complex and extensive. Some of these have been 

 described in Mr. Martin's work already referred to ; and of others, more re- 

 cently observed by that gentleman, I hope he will himself soon publish a 

 description:}:, 



* See Mantell's " Tabular Arrangement of the Organic Remains of Sussex" — Geol. Trans. 2nd 

 Series, vol, iii. p. 210, Terebratulae are there mentioned among the genera common to both 

 deposits. 



X The forces by which such derangements may have been effected, appear to be still in action 

 in this part of England. In tlie spring of the present year, 1 834, distinct shocks of an earthquake 

 were felt throughout a tract, of which Chicliester seems to have been the principal poir.t. At 

 Pulborough, they were of such force as to ring the bells at the parsonage. An account of the 

 phenomena, is, I believe, in preparation, by some members of the Philosophical Institution at 

 Chichester. 



X 2 



