418 A. J. JUKES-BROWNE ON THE HESSLE 
later than the Chalky Boulder-clay. All I have attempted to show 
in the preceding pages is, that the grounds on which the older gravels 
haye been correlated with the Hessle Sands cannot be sustained in 
the light of more recent researches; and I contend that it is wiser 
to suspend our judgment concerning the relations which they bear 
to the Glacial series until more positive evidence has been obtained. 
APPENDIX. 
The Deep Well at Boston. 
' Great importance has recently been given to the details of a deep 
boring at Boston, which was executed in 1828, and a record of which 
is preserved in Thomson’s ‘ History of Boston.’ This account has 
been reproduced in the ‘Memoir on the Geology of the Fenland,’ 
by Mr. 8. B. J. Skertchly. Depending on this record, and mainly 
on the fact that between the depths of 523 and 530 feet “ clay, 
shells, and flints” are said to have occurred, Mr. Skertchly regards 
the section as giving evidence of the extension of the Glacial series 
to the enormous depth of nearly 600 feet below Boston. 
I cannot but think, however, that the evidence on which this sup- 
position rests is too weak and uncertain to support so startling a 
conclusion. The description of the beds said to have occurred in the 
last 80 feet is certainly very extraordinary; buta boring can never 
be considered of the same evidential value as a section which has 
at any time been open to observation, and this boring is 50 years 
old; so that no questions can be asked of the well-sinker. Every 
one who is accustomed to the reports of such persons is aware of 
the extraordinary terms they sometimes use, of the necessity there 
often is for personal cross-examination, and of the liability to error 
arising from stones and other substances falling into the bore: this 
error is particularly difficult to eliminate ; and I think it may account 
for some of the appearances in the present case. 
Furthermore it is always necessary to translate such accounts 
into geological language ; and it is not always safe to accept the well- 
sinker’s terms in a literal sense. Now in this particular record fre- 
quent mention is made of shells, shingle, and flint; and Mr. Skertchly 
lays great stress on the occurrence of the last of these, because he 
thinks “this substance can hardly have been mistaken for any other 
material”’*. Mr. Penning, however, has drawn my attention to the 
fact that in Cambridgeshire the term “ flint” is said to be sometimes 
applied to hard beds and concretions in the Oolitic clays. Speaking 
of a rocky band in the Oxford Clay, Prof. Seeley says “the work- 
men call it ‘ flint,’ a name I have also found given in the surround- 
ing district to the septarious concretions of the clays”. 
The shells may, of course, be actual fossil shells (Ostrea, Gryphea, 
&c.); but a substance, which was probably selenite, has been de- 
scribed to me as coming up “‘in bits, like shell or pumice-stone.” 
What the shingle may have been is hard to say; but it would be 
* Geology of the Fenland, p. 211. 
t Seeley, Ann. & Mag. Nat. Hist. ser. 3, vol. x. p. 104. 
