The history and antiquities of Boston, and the villages of Skirbeck, Fishtoft, Freiston, Butterwick, Benington, Leverton, Leake, and Wrangle; comprising the hundred of Skirbeck, in the county of Lincoln. Including also a history of the East, West, and Wildmore fens, and copious notices of the Holland or Haut-Huntre fen ... sketches of the geology, natural history, botany, and agriculture of the district; a very extensive collection of archaisms and provincial words, local dialect, phrases, proverbs, omens, superstitions, etc. By Pishey Thompson. Illustrated with one hundred engravings.

GEOLOGY OF THE DISTRICT. 669
alluvial silt, clay, sand, and gravel, which, though not regularly stratified, has in all probability beds of gravel or loose sand in it, sufficiently uniform and extensive, to form communications with the salt-water in the river, or perhaps with that in the ocean, and thence
to supply all the salt-water, which is mentioned at 49 feet, 115 feet, 255 feet, and 468 feet
of depths, all which came, I think, into the bore-hole by this means alone; for, as freshwater springs would have powerfully risen (for reasons which I shall give further on), if any
such had been penetrated by the augur, I may, I think, conclude that the salt-water, which
is said to have been drawn up from the two lower points (225 and 468 feet), did not ouze
into the bole-hole at those depths, but that the same was introduced there, from the alluvial springs above-mentioned, at the times of drawing up the augur with its charge, when a
current of water would each time rush down to supply the space below the bit.
"There is a material distinction to be observed with regard to the term gravel, which has
hitherto been overlooked by most practical well-diggers and borers, for they call the rubble
of any loose rock or small pieces of stony substance, which their augurs or buckets bring up
out of the earth, by the name of gravel, instead of confining that term to alluvial mixtures
of broken and worn stones; in which sense, gravel has never, I believe, been found under
any regular and undisturbed strata, but always upon such, in accidental heaps, rather than
in very extended strata.
"The ragstone mentioned at 481 feet, and the gravel at 115 feet 2 inches of depths,
were, as I conceive, only layers of the extraneous fossils or stony nodules called ludus
helmontii, with which this clay abounds, and possibly these may, in this case, form such a
continuous bed as to communicate with the sea, and produce salt-springs, because the
layers of such nodules or clay balls, in the London clay strata, are known to produce small
springs in several places in the wells of Middlesex and Surrey.
"' The chalk, small pebbles, and flints, if any such were really brought up from the depth
of 1741 feet, could, as I conceive, have come there only by falling down the hole from the
alluvial gravel first mentioned, after being detached by the friction and swagging of the
rods, or by the nose of the augur in returning it into the hole; and this inconvenience
seems to have been so often experienced as to occasion the necessity, after they had bored
to the depth of 444 feet, of putting down tin, and afterwards iron pipes, to guide the upper
part of the rods, and prevent their action on the gravel and stones round the hole; yet I
see no reason to conclude that this precaution should absolutely prevent the further fall of
small gravel and chalk stones from near the top, and that such might not still pass withoutside the tubes, and reach the bottom of the hole; and in this way I think it easy to
account for the gravels and chalks, which are mentioned at 449 feet 10 inches, 454
feet 7 inches, 456 feet 8 inches, 457 feet, 470 feet 7 inches, 472 feet, and 472 feet
3 inches of depths; and, after all, without being able to inspect and examine the identical matters bored up (which, as far as I could learn, are not preserved), I see no evidence
to contradict a supposition that many of these, denominated gravel and chalk, were in
reality fragments and chippings of ludus helmontii, or of clunch, the borings of either of
which might too much resemble chalk to be easily distinguished therefrom.
" I have been thus particular, respecting the borings by Thomas Partridge and George
Naylor, because your question, as to the probable distance which must be further bored or
sunk before a spring of water will be found, entirely depends for an answer, upon ascertain.ing the fact, whether alluvial gravel had really ceased after 371 feet of depth, and the ciunchclay strata commenced. I shall, therefore, proceed to mention some other circumstances
which have conduced towards fixing my opinion, that the borings, after the first 371 feet
were actually in the clunch-clay: these are, first, the ascertained fact, that this assemblage of
clay strata, or some of them, actually descend at the edge of the northern border of the
fens, and pass under them all the way from Bolingbroke to Tattershall; the same having
been penetrated, and their proper extraneous fossils exposed, in various parts of the new
catch-water drain. Secondly, if you do me the honour to compare my account of the clay
strata in Hareby Sand Hill, near Bolingbroke, with the Boston borings, considering the first
clay of 15 feet 10 inches thick, as the same as that, of which 101 feet remains under the
372 feet of alluvial deposits at Boston, you will, I think, perceive all the marks of identity
which can be expected in two parts of the same stratum at the distance of 15 miles from
each other;'the dark-blue clay resembling blacklead,' in the Boston borings, agreeing, as
well as could be expected, with the dark bituminated clays, occurring in the last 681 feet of
my levellings near Bolingbroke. Thirdly, MIr. William Hobson, in the last year, employed
persons to bore in search of coal upon the farm in Raithby in his occupation; which, at the
time when I visited the spot, and received information from him in writing on the subject,
had extended to the depth of 312 feet, without meeting with any spring of water; and the
only substances reported by his borers to have been penetrated, except clay, were such as
coal-borers, in various parts of England, have hitherto denominated coal-slate, &c.; but