418 PEOCEEDII?^GS OF THE GEOLOGICAL SOCIETY. [Mar. 21, 



27. Natica Ilantoniensis, Sow. ? From Oldhaven sand. 



28. cantenoides, 'Wood?=iV". glaucinoides, Sow. From Old- 

 haven sand. This seems to be the common Eocene N. la- 

 hellata, Lam., which also=iV. glaucinoides, Sow., this last 

 name seeming to have been given both to a Crag and to an 

 Eocene species. 



29. Bulla concinna, "Wood. I did not see this. 



30. utricula, Nyst. Erom Oldhaven sand. 



31. Dentalium, new sp. ? Perhaps from Oldhaven sand. 



32. Helicc, "adhering to a broken FususJ' The latter is from the 



Oldhaven sand ; but the former is a recent species, and 

 clearly came from a modern freshwater deposit, like that of 

 Copford (Essex), or from a valley-drift, like that of Chislet, 

 close to Grove Eerry (see Prestwich in Quart. Journ. Geol. 

 Soc. vol. xi. p. 110), and has stuck on to the Eocene shell 

 by chance. 



33. Mingicida. I did not see this. 



34. Valvata piscinalis, MiiUer, " in sand within a Cardiimi Lay- 



toni." This seems to be nothing but the broken top of a 

 Natica from the Oldhaven sand. 



35. LimacG. Source uncertain. 



I cannot help doubting others of the determinations in the above 

 list, besides those to which I have therein taken objection. A few 

 of the fossils, however, were new to me. 



There are some small otolithes in the collection, which seem to 

 have been left out of the list by mistake. I have also got parts of 

 the scutes of a Turtle and the teeth of Lamna in the same pit. 



§ 5. Genekal Eelations oe the Divisions op the " Lowek London 



TeETIAEIES " TO ONE ANOTHEE. 



1. The TJianet Beds are the most regular of the three series. They 

 steadily thin away westwards ; whilst eastwards from their central 

 district, near Kochester, fresh beds come on above, and partly perhaps 

 replace the sand (c), giving the whole a more clayey character. 



Wherever a good section of the junction with the Chalk is to be 

 seen, that junction is even ard does not show unconformity. There 

 is indeed no stratigraphical proof of unconformity between the 

 Thanet Beds and the Chalk. 



I must quote some remarks of Mr. Prestwich, which might seem 

 to differ from the above. " Extensive and deep wear of the Chalk 

 evidently took place before the commencement of the lowest Eocene 



deposits. In the neighbourhood of Pegwell Bay, Upnor, 



Woolwich , Beading, Newbury, , and Alum Bay, the 



Chalk invariably presents a worn though not very irregular surface, 



and is strewed over with those peculiar green-coated flints. 



This mass of flints, although generally not above 1 or 2 feet thick, 

 in itself indicates a wide destruction of the Chalk "*. I think that 

 Mr. Prestwich wiU now allow that any irregularity that occurs at 



* Quart. Journ. Geol. Soc. vol. viii. p. 256 (1852). 



