1846.] PRESTWICH ON THE ISLE OF WIGHT TERTIARIES. 



259 



Description of Strata. 



6. Dark brown sandy clay with two 

 layers of septaria. A few remains of shells 

 and traces of plants occur in this bed, toge 

 ther with a seam of small flint pebbles. Top 

 of the bed darkest and most fossiliferous. 

 A small fault dipping 50° W. occurs in this 

 bed. 



5. Sulphur-yellow grey sand with seams 

 of dark grey clay. No fossils. Passes 

 into (4). 



4. Dark brown clay, with several layers 

 of septaria, and one thin band of calcareous 

 greenish grey sandstone. The lower part 

 slightly red. At the bottom a thickness of 

 one to two feet is mixed with sand, and 

 contains large rounded flint pebbles. An- 

 other layer of small flint pebbles occurs near 

 the centre. Organic remains, which are 

 scarce in the lower part, are numerous 

 higher up, especially in the bed containing 

 the small pebbles. Among the large peb- 

 bles at the bottom sharks' teeth are found, 

 and in the lower part of this stratum also 

 Mr. Bowerbank found the Cancer Leachii. 

 Reposes upon a slightly uneven surface 

 .of (3). 



3. Yellow sands and clays with traces of 

 Ugnite. Irregular. 



2. Mottled clays with traces of lignite. 

 The following, in descending order, are the 

 colours of the nine layers composing this 

 stratum. In each layer the colours are 

 mottled : — red and very light bluish grey 

 and yellow ; light and dark slate -coloured ; 

 red and yellow ; brown, red and yellow ; 

 red, lavender, puce and yellow ; brown and 

 blue ; red and grey ; grey and brown ; blue, 

 red and brown; brown and blue. The 

 layers are indistinctly separable. 



1. Coarsish dirty yellow sand with large 

 flints underlying, of the same character as 

 those of the upper chalk layers, and a few 

 _ small round flint pebbles. 



Feet, 

 1376 



135 



86 



1664 



Association of genera and 



characteristic species in the 



chief fossiliferous beds. 



6-4. 



Panopsea intermedia. 



P. virgula. 



Pectunculus brevirostris. 



Vermetus Bognorensis. 



Rostellaria Sowerbyi. 



Pholadomya margarita- 

 cea. 



Turritella imbricataria, 

 var. 



Pinna affinis. 



Ostrea, 2 sp. 



Dentalium (Ditrupa) pla- 

 num. 



Venericardia planicosta- 

 ta, var. .' Suessonensis. 



Pyrula. 



Calyptrsea trochiformis. 



Natica. 



Fusus. 



Corbula. 



Cerithium. 



Pleurotoma. 



Lutraria. 



No organic remains of 

 animals yet discovered. 



Chalk, with flints. Upper surface worn and uneven. 



Note. — Mr. Webster's sands and plastic clay include strata Nos. 1 to 28 at Alum Bay, and 

 the London clay of that author is No. 29. The strata are more subdi\'ided at Alum Hay than at 

 WhiteclifF Bay, chieHy on account of tlicir being more perfectly exhibited in the former. It 

 should be understood that the lines of »ei)aration between the ui)pcr uud lower divisions of the 

 upper group at Headon Hill are only anproximative, and that the lists of orgauic reuiains do not 

 include all tliose found, but are intcncied to intimate that such species or geuora occur in some 

 part of the series associated with others, which are either less abundant or more necessary to the 

 argument, and which therefore in the latter case are mentioned in the text. 



