J. S. GARDNER ON THE LOWER LONDON TEKTIARIES. 207 



whitish, weathering a rusty brown, giving a green streak to the tool 

 when struck, and containing much woody matter and large green 

 grains *. It is a compact bed with an uneven upper surface very 

 distinct from the overlying blue London Clay. When last seen the 

 Oldhaven Beds appear comparatively indurated and of the ordinary 

 buff colour of sand when dry, and greenish grey when wet. 



Fossils last appear about 7 feet below the junction, and 200 feet 

 east of the disappearance of the beds, drifted into pockets, though a 

 little east of the latter irregular lines of fossils approach within 

 5 feet of the junction. 



These Oldhaven Beds can be traced a long way inland without any 

 change in character, and are immediately recognizable by their base 

 of black pebbles. Their fauna is very rich, far richer than the Survey 

 list of 1872 would lead us to suppose, and approximating more closely 

 to that of the London Clay than has been admitted ; but among 

 masses of comminuted shells only one here and there is perfect. I 

 have not observed any very local distribution among them, except 

 in the case of a large Aporrhais, all the specimens of which were 

 found close together. By far the commonest shells are Cytlierea and 

 Protocardium. The tidal and surf-action is everywhere apparent, 

 and their origin is unmistakable ; but whether they were formed, as 

 I believe, on a coast-line, or on banks away from shore, is less ap- 

 parent, the absence of unworn flints showing at least that no chalk 

 was present in the immediate vicinity. The greater variety of the 

 Mollusca may be accounted for by dead shells being heaped together 

 from various depths, as we see at the present day on coasts ; but the 

 presence of a few turtle bones, taken with evidence gathered else- 

 where, must also indicate that the increase of temperature had 

 already commenced. We see by the Survey list of fossils that the 

 fauna was intermediate between those of the London Clay and the 

 Thanet Beds ; for only two species are now not known to range 

 beyond it ; 7 of the species range downward only, 12 range both up 

 and down, and 13 range upward only ; so that it is united by 75 per 

 cent, of its species with the London Clay, and by 50 per cent, with 

 the Thanet Beds. 



It is thus certain that there is but one break in the marine deposits 

 of the Lower Eocene in East Kent ; and I cannot help thinking that 

 it would be far more convenient to retain the name Thanet Beds 

 alone for the lower division. A great interval may have elapsed 

 between these and the Oldhaven Beds, which belong palaeontologicalry 

 to the London-Clay series. The Oldhaven Beds might fairly be con- 

 sidered, as I shall show, to be a lower member of the latter series, 

 as, indeed, was implied by Prestwich's name for them. The upper 

 portion of the marine Thanet Beds of this part of Kent may have 

 been, and probably was, to a slight extent contemporaneous with the 

 fluviatile Woolwich-and-Reading Beds of further west. The incoming 

 of these cannot be traced on this coast ; and there is no section appa- 

 rently revealing them until the neighbourhood of Chatham is reached, 



* The lower beds of London Clay are here tenacious and blue even when 

 weathered. 



