Beacon Cliff, and Barton Cliff, Hampshire. 291 



4thly. The strata of Hordwell Cliff correspond with those on the opposite 

 side of the Solent, particularly with the lower freshwater beds between Yar- 

 mouth and Gurnet Point : where, as Professor Sedgwick observes*, they lose 

 the appearance of an indurated calcareous marl, and are not unfrequently of 

 a bright green colour, and preserve their continuity for a great extent. " In a 

 part of the coast between Yarmouth and Hampstead Cliff," he adds, '^'the beds 

 are brought out from one under another in a long succession. The whole 

 formation is subdivided by almost innumerable layers of fossil shells, which 

 follow the planes of stratification. The beautiful preservation even of the 

 minutest characters both of the bivalves and of the univalves, and still more the 

 arrangement in distinct families, afford a proof not short of demonstration that 

 the whole system has originated in a tranquil deposition." Professor Sedg- 

 wick's description is equally applicable to the strata on the Hampshire coast; 

 and the genera of shells enumerated by him are the same, as far as they go, 

 with those which I have mentioned. Although no doubt can be entertained 

 that the strata of Hordwell Cliff belong exclusively to what has been termed in 

 the Isle of Wight the Lower Freshwater Formation, yet it may be a question 

 whether the organic remains are not of a mixed nature, some few examples 

 presenting themselves of shells belonging to marine genera. Thus a small 

 mytilus occurs in two of the beds, and, in two instances, a small serpula ; the 

 latter shell was found also by Professor Sedgwick in Hampstead Clifff in the 

 Isle of Wight. But although these latter testacea may have required salt- 

 water, they may very probably have inhabited the estuary of a river within 

 the influence of the tides ; for the whole assemblage of organic remains is so 

 precisely similar to that which characterizes recent freshwater deposits, and 

 there are so many proofs of tranquil deposition, that we cannot suppose them 

 to have been all washed by the violence of floods into the sea. 



The plentiful exuviae of the cypris|, as well as the gyrogonites§, are 

 positive indications of the freshwater origin of this formation. The small 

 number of genera and species to which the shells are referrible, though the 



* Ann. of Phil, for 1823, vol. iii. p. 347. 



f Sowerby Min. Con. No. 91, description of Tab. 527. 



X Lamarck observes in bis work " Animaux sans Vertebres," that these microscopic entomo- 

 straca change their skin and shell at the same time. They inhabit the fresh and stagnant waters 

 of marshes and ditches, and swim swiftly. Vol. v. p. 124. 



§ These fossil seed-vessels have been found by some collectors in Hordwell Cliff in great abun- 

 dance, in some of the fine white sands. The fine sand of the Thames, used for covering the floors 

 of kitchens in London, is often filled in a similar manner with the seed-vessels of recent CharjE. 

 The integument is so tough that the spiral ridges on the surface retain their sharpness as in their 

 fossil analogues, unefFaced by the attrition of the sand. 



