1866.] WHITAKEK LOWEE LONDON TEETIAEIES. 431 



decided opinion on it, but rather of showing how careful we should 

 be in doing so. 



Mr. Prestwich's reasons for classing these sands with the Crag 

 are, that they are different in structure from the neighbouring old 

 Tertiary beds, and that many of their fossils are like those of the 

 Crag. Now it has been shown, in the foregoing part of this paper, 

 that there are irregularities in the Lower London Tertiaries, by means 

 of which outliers of the upper and middle divisions occur resting at 

 once on the chalk, without the presence of the lower division, the 

 Thanet Beds, and also that those divisions often change their struc- 

 ture. May not, therefore, the peculiar features of these outlying- 

 sands be explained on the supposition that they are transgressive 

 parts of the "Woolwich and Oldhaven Beds ? 



I should not venture to make this suggestion were the fossil- 

 evidence more trustworthy. In Mr. Wood's list, appended to Mr. 

 .Prestwich's paper, the name of every species is followed by a note 

 of interrogation ; and, in the words of that palaeontologist, " the 

 most that can be said is, that there is a stronger resemblance in 

 these fossils to the shells of Crag than to those of any other forma- 

 tion." Since the publication of the above, fresh fossils have been 

 found by my colleague Mr. Hughes and myself, but they do not 

 throw much light on the question. All are in the state of casts or 

 impressions, and are therefore hard to determine. There are amongst 

 them specimens which many palaeontologists would at once refer to 

 Crag species, especially perhaps a large TelJina exactly like T. Bene- 

 denii (?), and a Panopcea like P. Faujasii ; others, however, would 

 do equally well for Eocene species ; and some can hardly be classed 

 as of any other age than Eocene — for instance, some specimens of 

 Phoriis quite like P. agglutinans, a Cyrena cuneiformis, and some 

 examples of a small Nucula (which Mr. J. G. Jeffreys, F.E.S., tells 

 me is quite unlike any that occurs in the Crag, whilst it seems to 

 be rather the Eocene N. minor). When discussing this question, I 

 have sometimes been met with the statement that the finding of 

 the large Terehratula of the Crag {T. grandis) in the Lenham iron- 

 stone settles the matter ; but against this there is the fact, pointed 

 out to me by Mr. Charlesworth, that this shell has been recorded as 

 occurring in Eocene beds in England, under the synonym of T. hisi~ 

 miata, by no less an authority than Mr. Davidson*. It seems, 

 therefore, that we cannot get much help from the fossils. I would 

 add that our knowledge of those from the Kentish Tertiaries is yet 

 far from perfect ; fresh species (both new and recorded before from 

 higher beds only) often turn up ; so that some of the anomalies of 

 the Lenham list may perhaps be explained when the fossils of the 

 older Tertiary beds are better known. 



Another element of doubt is, that the fossils occur only in the 

 ironstone of some pipes at Lenham, none having been found in the 

 larger masses of these sands at Paddlesworth &c.t — and yet another 



^ Monogr. Palseont. Soc. 



+ My colleague, Mr. Topley, has lately found a cast of a bivalve (C^-^rina?) 

 in a field on the hills above Folkestone. 



