LENHAM BEDS. 
43 
decided species exclusively belonging to the Older Tertiaries.” 
Further on he remarked that “ still, if it be asked whether a 
perfect reliance can be placed upon any speeimens as truly 
characteristic of the Crag period, I fear an answer must be given 
in the negative, although the general aspect of the fossils is 
certainly favourable to the assumption that they belonged to 
the Upper rather than to the Lower Tertiaries/’ And com¬ 
menting on the list he added, The accompanying list contains 
the names of those species to which they bear a very close re¬ 
semblance. I give them as approximations only; and, although 
there is not one which without a doubt could be satisfactorily 
determined, I still think that, taken collectively, they are such as 
to justify a probable assignment to one of the Crag periods, and 
they appear to have been inhabitants principally of the Coralline 
zone.” 
Prof. Prestwich, commenting on Wood’s note, speaks much 
more decidedly, for he writes: I must confess to hold a stronger 
opinion on the subject than Mr. Wood, for there are collateral 
circumstances which greatly strengthen my belief of these beds 
belonging to the Crag, little as I was prepared to meet with the 
Crag at such an elevation and such a distance from the main 
mass. In the first place, I know of no Eocene strata in the 
London Tertiary area quite like this deposit in its lithological 
structure.And fourthly, because I find similar 
beds on the chalk-downs on the opposite side of the Channel, 
between Calais and Boulogne; and tbence, passing across the 
plain of French Flanders, we again meet with analogous strata,— 
though more important and with more ironstone, —on the top of 
Cassell Hill, 515 feet above the sea, and overlying the Calcaire 
grassier series.* * * § ^^ 
Owing to the unsatisfactory state of preservation of the specimens, 
and perhaps also to an accidental mixture of Eocene fossils from 
another locality, this discovery was afterwards generally discre¬ 
dited or ignored. Prof. Prestwich himself has, however, always 
maintained its accuracy, and several foreign geologists have 
supported him. 
Lyell in 1865t treated the Lenham ironstones as a continuation 
of the similar sands at Diest, and classed them doubtfully as Upper 
Miocene; but in 1866, according to Mr. Whitaker, he had given 
up this view, and the deposits are entirely ignored in subsequent 
editions of his works. 
In 1862 Mr. Whitaker was inclined to refer the sands to the 
Crag,J but in 1866,§ and 1872,|| he thinks rather that they may 
* Prestwich. On the Age of some Sands and Iron-Sandstones on the North 
Downs. With a Note on the Fossils; by S. V. Wood. Quart. Journ. Geol. Soc., 
vol. xiv. pp. 322-335. (1858.) 
f Elements of Geology, 6th Edit. pp. 223, 368. 
X Quart. Journ^ Geol. Soc., vol. xviii. p. 273. 
§ Ibid., vol. xxii. pp. 430-433. 
li The Geology of the London Basin {Memoirs of the Geological Survey), pp. 336- 
342, 601. 
