1824.} below the Chalk, be. 383 



yet had an opportunity of comparing the specimens, with those 

 of the Whetstone quarries at Blackdown, in Devonshire, which 

 are in the green sand. 



Fig. 3, is a section southwards from the chalk near this 

 place to the town of Swanage, but reversed, for the purpose of 

 showing its correspondence with that of the Isle of Wight at 

 Compton Bay : and I have also copied a portion of Mr. Web- 

 ster's accurate view of the coast, for the purpose of pointing out 

 more precisely the situation of the clays.* — In this sketch (rio-. 4) 

 the spectator is supposed to be placed upon the firestone where 

 that bed first rises from under the chalk, and to look alono- 

 the shore towards Swanage. Masses of fallen chalk are seen 

 between this place and the commencement of the Hastings 

 sands : — but these are easily accounted for, — being in fact an 

 underclifF, produced exactly in the same manner as in the Isle 

 of Wight : — and the firestone and gault rise and hold their 

 place with as much regularity as I have any where else remarked. 



The section of the Hastings sands, in Swanage Bay, com- 

 prehends the whole of the formation, and gives one of the 

 most distinct views of it that can be obtained in England. It 

 corresponds completely, at the upper part, with the beds which 

 are visible in the isle of Wight, and at Hastings. 



VI. Very little is yet known of the strata which form the 

 subject of this paper, in the interior of England; but an atten- 

 tive perusal of Mr. Conybeare's descriptions will show that 

 some of the obscurities connected with them, may be re- 

 solved by referring to the order in which the beds are exhibited 

 in the Isle of Wight. I am in fact unwilling to abandon the ex- 

 pectation of finding in this part of the series the same steadi- 

 ness of arrangement, that is known to exist in other portions of 

 it : the reasoning which implies, that less of regularity is to 

 be expected in a suite of sands and clays than elsewhere, hav- 

 ing always appeared to me to be insufficient. It is the fact 

 alone, established by extensive observation, that could have 

 rendered credible the identity and constancy of succession of 

 any portion of the stiata; and we really know so very little of 

 the mode in which they have been formed, that our estimate of 

 the comparative probability of regularity in one description of 

 beds, of sand, or clay, or limestone, more than another, is matter 

 of the very slightest conjecture. 



* The place where all the beds above described occur is called Punfield. The ex- 

 amination of it is rendered difficult by the position of the strata, which retire obliquely 

 inland, and at the same time, when seen from the shore, rise towards the eye ; so 

 that the weald clay lies behind the upper beds of the Hastings sand, in a nook, where it is 

 so much obscured by the fall of the incumbent substances, that without the assistance 

 of quarry-incn I could not have obtained a view of the beds in situ. 



