Mr. Webster on a Fresh-water Formation in tlordwell Cliff, Sgc. 93 



flattened ovoid fornix, with the surface corrugated^ and having a portion of the 

 process by which they were attached still remaining : they are all hollow, and 

 are in general divided, appearing as if they had burst open. They consist in 

 their present state of lignite penetrated by pyritous matter. Fig. 3, Plate 

 XII. represents one of these bodies of the natural size: and at fig. 4 are 

 magnified views of it. 



Towards the lower part of these fresh-water beds, there are numerous frag- 

 ments of lignite, and beds a few inches thick of a substance resembling what 

 the French call tourbe pyriteux. 



Immediately below this formation at Hordwell, is found a bed of sand from 

 sixty to one hundred feet thick : which appears first about Long-mead End, and 

 maybe well observed in the section at Beacon Bunny. This remarkable bed 

 of sand forms one-half of the height of Barton Cliff, and is seen in the upper 

 part of High Cliff", where it thins olf and terminates beneath the gravel. 



The bed which is identical with the London clay lies immediately below 

 this sand : it commences on the east, at the level of the sea, between Long- 

 mead End and Beacon Bunny, and extends through Barton and High Cliffs : 

 but it is in the upper part only that the fossils are numerous. This part of the 

 bed may be twenty or thirty feet thick, and consists of a very sandy clay of a 

 dark-green colour. Beneath it are some layers of large septaria ; and there 

 the clay is much less sandy, and contains fewer fossils. It is about Beacon 

 Bunny that the fossils are found most conveniently ; the upper part of the bed 

 being easily accessible in that place : as the stratum increases in height, 

 particularly at High Cliff, it is more difficult to reach the green bed. About 

 Chuton Bunny are many large water-worn stony masses, with shells derived 

 from beds in the London clay : and about the middle of the length of this cliff" 

 a stratum of sand appears below the clay, from which it is separated by a thin 

 layer of rounded pebbles. This sand is of a dirty white, and contains many 

 fragments of lignite, among which parts of branches, and a few even of the 

 leaves of plants, may be distinguished. From its situation I consider this as 

 the sand of the plastic clay : the fragments of vegetables, also, being very like 

 those which accompany the lignite of that formation at Alum Bay. This bed 

 is suddenly cut off by denudation before it reaches Muddiford, and then gravel 

 forms the low cliff", which extends nearly to that place. 



From a variety of reasons, I am induced to consider the fresh-water bed at 

 Hordwell as corresponding to the lower freshwater formation of the Isle of 

 Wight. I have lately found this at East Covves, at low water, with the same 

 characters as at Hordwell : the beautiful green clay with Limnei and Pla- 

 norbes being similar at both places. In my former paper, I mentioned that I 



