288 Mr. Lyell on the Freshwater Strata of Hordwell Cliff, 



1. Diluvial gravel composed of broken chalk flints with occasional layers of sand and marl, vary. 



ing in height from 5 to 50 feet. 



2. Fine white sand, sometimes containing in the lower part layers of light green marl frequently 



stained with iron, from 3 to 12 feet. 



3. Green marls, which may be thus divided, beginning with the upper beds : — 



a. Greenish unctuous marl without shells, varying from 1 to 3 feet. 



b. Dark leaden-coloured greenish clay. Contains bituminized wood and numerous seeds or 



capsules of plants (figured PI. XII. Geol. Trans. Part 1. vol. 1. 2nd series); and the 

 following shells. Unio Solandri (Min. Con. tab. 517.). This shell is abundant, but in 

 a very fragile state. The nacre of the shell is well preserved ; sometimes, but rarely, 

 it is found perfect with its brown covering. Helix lenta (Brander) in great abundance. 

 Melania, in the lower part of the bed, in a very perfect state, a shell not yet described 

 in any publication. The thickness of this bed, which is well seen at the Mine Way, is 

 about one foot and a half. 



c. Green marl, with the same seeds as above ; also containing unio Solandri, helix lenta, 



and melanise in abundance, and fragments of another conical shell (perhaps part of the 

 spire of a lymnaja ?). The green marls containing melanin are found in the ruins of the 

 cliff between the Mine Way and IIordwell-End-Lane, in large fallen masses; and the 

 bed to which they belong will appear to be often repeated, unless great caution is used. 



d. Marl of a beautiful bright green colour, characterized by melanopsis carinata (Min. Con. 



tab. 523. fig. 1.) ; containing also helix lenta and planorbis lens (Min. Con. tab. 140. 

 fig. 4.); also fragments of lymnsa fusiformis*(Min. Con. tab. 169. fig. 2, 3.). 



e. Arenaceo-argillaceous marl dividing into laminae, occasioned in some degree by exceed- 



ingly minute fragments of unio Solandri disposed in parallel layers, and resembling 

 mica. The position of this sandy bed is not easily ascertained in the above group, in 

 consequence of the ruined state of the cliffs. Unio Solandri occurs in this bed unbroken, 

 and the seeds noted in 3. b. ; also numerous valves of a small cypris of a yellow colour, 

 in layers, as the cypris occurs in the Weald clay. Thickness of c. d. e. about 12 feet. 

 Total thickness of No. 3. about 16 feet. 



4. Sands and clays, which may be thus divided : — 



a. Greenish brown sand, 8 inches. 



b. Brown laminated clay, and bituminous dark clay with lignite, one foot and a half thick. 



c. Marls of various shades of green, 12 feet. 



d. Bright green marl ; in the lower part, mya gregarea (Min. Con. tab. 363.) in great 



numbers and very perfect, lying on their sides parallel to the pianos of stratification : 

 this bed is about one foot and a half thick. Thickness of No. 4, about 15 feet. 



5. a. Calcareous marl, sometimes slightly indurated, consisting of aggregated shells, planorbis 

 rotundatus (Brard.), and lymnaea longiscata(Min. Con. tab. 343.), in a very fragile state 

 and generally broken. A small species of lymnaja (columellaris Sow. Min. Con. tab. 528. 

 fig. 2.), occurs, rarely; also L. fusiformis. In some parts, as about 200 yards East of 

 IIordwell-Lane-End, where it first rises, this bed contains gyrogonites (chara Medica- 

 ginula) in abundance. Although this bed is only from six to eight inches thick, it is very 

 conspicuous from its light colour and the black bed of carbonaceous matter immediately 

 below it. 



