592 



MESSES. GAEDNER, KEEPm&, AJSV MOXCKTON ON THE 



fossiliferous here and at Whitecliff Bay, and contain many Barton 

 types. Judd, on the other hand, -^hile admitting that " these beds 

 graduate so imperceptibly into the underlying Barton Clays that it 

 is difficult to fix the exact hmits between them"*, decided to sepa- 

 rate them on account of their more estuarine character, and would 

 have them called the "Headon Hill Sands.'"' They seem to us, 

 however, to be more closely related to the Barton below than to 

 the Headon above, and we prefer to retain them in the former, 

 distinguishing them locally as the Becton-Bimny Beds. 



They are divisible into an upper and a lower division. The latter 

 rests on the CTia-ma-hed, the separating line being well marked, and 

 consists of a mass from 20 to 25 feet thick, of fine, at first ashy 

 grey, piped, unfossiliferous^, very angular sand, in which Mr. Cole 

 detects numerous flakes of Muscovite mica, becoming almost pure 

 white and then pale grey, mottled with darker grey. This sand 

 contains much alum, is feebly plastic, maintains itself at a high 

 angle, and is not loosened and blown by the wind. Its upper 

 surface is xeTj uneven, and it is piped throughout, as if it had been 

 thickly inhabited by large bivalves and Annelids. It is overlain by 

 sand of an earthy colour, full of casts of shells, and then by a stiff 

 sandy clay of blackish or bluish colour f, becoming more and more 

 sandy and full of sheUs. Towards the bottom the prevailing forms 

 are Oliva Branderi, Cei^thium variabile, Vicarya, Ancillaria^ Naticciy 

 Cardita, Lucina, Mactra, Tellina. In the upper part of the bed a 

 more distinctly brackish-water assemblage appears, including Ceri- 

 tJiium and Marginella, Cyrena, Mytilus, B/^eissena, and Potamomya, 

 The accompanpng diagram (fig. 1) will enable them to be identified 



Fig. 1. — Section of Becton-Bunny Beds. 



I 





a. High fence between Col. Clinton's and the Hinton-Admiral estate. 



b. Gravel. c. Long-Mead -End Bed. 



d. Becton-Bunny Beds : Oliva-Branderi zone. e. Chama-hQ^. 



in the cliffs themselves. The bed terminates with a band, 10 inches 

 thick, of dark olive- green sandy clay, containing some of the above 

 fossils, together with Neritina concava, Lucina, &c. This part of the 



* Quart. Journ. Geol. Soc. vol. xxxviii. (1882) p. 475. 



t Mr. Grenville Cole describes this as a very fine, stiety clay, wben not con- 

 taining minute plates and rod-hte particles, "with some angular grained sand. 



