170 J. L. LOBLEY THE EOCENES OF ENGLAND 



scattered small blue-black pebbles, but without those thick beds of 

 pebbles — the Oldhaven Beds — seen at Blackheath and other parts 

 of Kent, and which in that county underlie the London Clay. 



Occupying the whole of the Tertiary area, excepting the fringe, 

 and two small areas near Northaw, where streams have cut through 

 to the Woolwich Beds, the London Clay forms the base on which 

 rest all the superficial Post-Pliocene or Drift deposits of this part 

 of the county. The thickness of the clay varies considerably, as 

 may be seen from the well-sections in the county, given by Mr. 

 Whitaker in his 'Geology of the London Basin,' which work should 

 be consulted by all who desire to have a good knowledge of the 

 geology of this district. 



As only the basement and lower beds of the London Clay are 

 present, the London Clay fossils of Hertfordshire do not adequately 

 represent the fauna of the formation, and we consequently look in 

 vain for the chclonian remains, the great nautiH, and the abundant 

 gastcropods and lamellibranchs of other areas. It must not be 

 supposed, however, that the organic remains found in the Eocenes 

 of Hertfordshire are devoid of interest. This is far from being the 

 case. Teeth of fishes of the genus Lamna are common, and Mr. 

 "Whitaker mentions the following species of Mollusca as occurring 

 at Bushey : — 



Aporrhais Sowerhyi, Mant. Cytherea ovalis, Sby. 



Oardium nitens, Sby. Nucula, sp. 



„ Plumsteadiense, Sby. Fanopma intermedia, Sby. 



Cytherea obliqua, Desh. 

 Besides these, a member of our Society, Mr. W. T. Stone, 

 som(! years since was fortunate enough to secure for science a 

 fossil determined by Prof. Owen to be a portion of a bone of a 

 monkey {Uyracotherium leporinum). The palaeontology of the 

 Eocenes of Hertfordshire is therefore worthy of the attention of 

 our geological members, who I hope may be able to add largely 

 in future years to our knowledge of the fossils of these beds, and I 

 trust, from what has been said of Hertfordshire, members generally 

 may be encouraged to devote some time to the study in the field 

 of the very interesting science of Geology. 



Appendix. 



WeLL-SECTIONS in HERTFORDSnrRE. 



(Abstracts of Sections in Whitaker's ' Geology of tho London 



Basin,' part 1, pp. 447-456.) 

 Amwell End. Baunet, New. Trial-borinsr mar 



Rough Gravel 36 feet. 



Chalk. 

 Baunet, East. Lion's Down. 



London Clay 113^ „ 



"Woolwich Beds 48^ „ 



Chalk. 

 Baunet, New. Railway Station. 



London Clay 115 ,, 



"Woolwich Beds 44 ,, 



Chalk. 



Railway Station. 



London Clay 111.', feet. 



Woohnch Beds 58 „ 



Chalk. 



The Absorbing Well. 



London Clay 73 



Woolwich Beds 08 



Bayfokd. 

 To Chalk 160 



