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rest on an eroded surface of the boulder clay, and pass upwards into that great series of sands, gravels, and shelly clays which form the cliff from Ramsey to the Point of Ayre. The shelly clays contain marine molluscs. Some of the gravels belong to the Kame series.
In North Wales there are many scattered drifts: Llandudno Mr. G. Maw has noticed pockets of chert, white sand, and white clay in the Mountain Limestone; these he thinks may be Pre-Glacial deposits. Mr. Mackintosh has described similar beds near Mold. At Colwyn (Rhos) Bay, and in the Peninsula of Wirral, he has noticed the threefold division of the Drift, which has been made out in Lancashire. At Colwyn the beds are underlaid by a blue clay containing striated stones, which Mr. Mackintosh has traced in places through the West Riding of Yorkshire and Cumberland. He has also described many Eskers in North Wales, Cheshire and Shropshire.
In the drift of Warwickshire, according to the Rev. P. B. Brodie, are boulders of sandstone, quartz pebbles, Chalk and flints, Oolites, Lias, Carboniferous Limestone, pebbles of Lower Silurian [or Cambrian] age containing some remarkable fossils identical with those which occur in similar pebbles in the Trias at Budleigh Salterton in Devonshire,
In the Midland Counties, Nottinghamshire, Derbyshire, Warwickshire, Leicestershire, and Northamptonshire, there
1 The term Kame is used in Scotland (Esker in Ireland and Åsar in Sweden) to denote certain peculiar ridges and mounds of drift which rest on the Boulder Clay and other Glacial Drifts, and regarding whese origin there has been much diversity of opinion. Some geologists maintain that they have been formed in the sea during submergence; others that they were produced by marine agency during the elevation of the area after submergence; some again consider that they are due to the action of subplacial waters (waters flowing underneath land-ice), or that they are morainic accumulations; while yet others have attributed them to torrential or fluviatile action,
are extensive deposits of Drift formed of rocks from many different formations, Chalk, Oolites, Lias, Coal Measures, Millstone Grit, Carboniferous Limestone, &c.
At Annesley, in Nottinghamshire, Mr. Aveline describes the gravel as sometimes cemented together into a breccia, and at Blidworth are some isolated masses popularly known as Druidical remains. These curious blocks were, no doubt, first roughly shaped out by the uncemented gravel having been denuded from around the cemented portions, leaving the latter standing high above the level of the ground. Some of these were afterwards shaped by men into their present forms.
In the Great Ponton cutting on the Great Northern Railway in Lincolnshire (to quote Professor Morris), 'we see the drift on either side of the cutting buoying up an enormous irregular mass of oolitic rock, through which the cutting has passed. This mass of rock is 430 feet long, and, at its deepest part, 30 feet thick; it is much broken and disturbed, but the parts retain to some extent their relative position, and belong to the lower portion of the Oolitic beds of the district.' He observes that although distinctly isolated, it retains sufficient uniformity of character to lead us to infer that it has not been far removed from its original site. This gigantic boulder is, however, not an isolated case, as other masses of Oolitic rock and Marlstone have been noticed in the district, sometimes of sufficient bulk to be quarried, while in the cliffs on the coast of Norfolk are large masses of Chalk which have been similarly drifted and re-deposited.'
· The following paragraph is taken from the work of Messrs. Conybeare and Phillips :- In the fields on the south of Sywell in Northamptopshire, the fragments of Chalk are so abundant as to give the appearance of a regular substratum of that substance, turned up by the plough. In the Philosophical Transactions for 1791 is an account of a Chalk pit found at Redlington in Rutland; which, if correct, must be considered as The drift-deposits of Yorkshire, Lincolnshire, and the Eastern Counties, have been most carefully investigated by Mr. S. V. Wood, jun., assisted by the Rev. J. L. Rome and Mr. F. W. Harmer. The following table exhibits their classification of the deposits :-
Hessle (Boulder) Cay.
Ilessle gravel (Kelsea Hill bed). Nar valley be·ds. Older Post-Glacial. Gravels and brickearths (connected with the denuda
tion of the Glacial beds during their emergence from
the great depression). The purple (Boulder) clay of Yorkshire without chalk,
passing down into Upper Glacial.
The purple (Boulder) clay with chalk, and containing
the Bridlington shell-bed.
The great chalky (Boulder) clay. Middle Glacial.
Sand, Gravel, and brickearth, with occasional seams 1 of boulder clay.
Contorted Drift. Lower Glacial. Cromer Till.
Bure Valley Beds : sée p. 290.
Prof. Phillips contended for the Pre-Glacial age of the Hessle Beds, but on the authority of Messrs. Wood and Rome they will here be treated of as Post-Glacial.
a relic of this destroyed tract. The account is rery precise, indicates a sufficient knowledge of the general nature and localities of the formation, and is such as to render the testimony very respectable ; but the poiut is so important that further enquiries are desirable. The Chalk is described as regularly interstratified with flints; and the surrounding district being entirely occupied by the ferruginous sands of the Inferior Oolite, it is not easy to conceive that it could have afforded any rock which could have been mistaken for Chalk. Another detached patch of Chalk is said, in the same place, tv exist near Stukely in Huntingdonshire on the banks of the Turnpike Road, but no particulars are given, and here soft varieties of other calcareous beds might be confounded with this substance.'
LOWER GLACIAL BEDS.
LOWER BOULDER CLAY.
The Lower Glacial Beds are estimated to have a maximum thickness of about 200 feet.
In no other part of England and Wales are these Glacial Beds so well shown as in the cliffs along the Norfolk coast, which in places rise to a height of 200 feet.
Cromer Till. The Cromer Till consists of a dark blue or grey sandy clay with numerous small pebbles of Chalk and other stones, and occasional large boulders of granitic rock, greenstone, and grit. Many of the stones show glacial striæ.
It generally rests upon the Bure Valley Beds, with which there appears in places to be some evidence of interstratification. It is not altogether persistent in the coast-section between Cromer and Happisburgh, but it forms a band that can readily be recognized. The junction with the beds above is not always very distinct; in some places there is a passage, in others there is evidence of local erosion, and the overlying beds occupy hollows on the surface of the Till. Inland it is inseparable from the Contorted Drift.
This deposit consists essentially of a brown stony loam, sometimes well stratified and containing seams of gravel and sand, at others containing seams of chalky loam or boulder clay, and exhibiting most violent and remarkable contortions.
Messrs. Wood and Harmer have noticed its occurrence in Suffolk, as a reddish-brown brickearth, resting on the pebbly sands (Bure Valley Beds).
It is, however, in the cliffs between Eccles and Weybourn that it can be best studied, and it there exhibits almost every variety of condition and contortion. The main portion of the cliffs is indeed made up of this usually brown loamy deposit, which rests on the blue Cromer Till. The contortions become conspicuous west of Mundesley, and thence near to Cromer, and between Cromer and Weybourn, seams of very chalky loam or boulder clay occur here and there in isolated irregular and lenticular masses. These are sometimes worked inland for lime.
Between East Runton and Woman Hythe are three large masses of transported Chalk which, by the weight of the bergs carrying them, bave sunk in some cases into the subjacent Till, and even into the Weybourn Sand (Bure Valley Beds).
The Contorted Drift is extensively worked for bricks around Norwich, North Walsham, Aylsham, and many other parts of Norfolk : it is sometimes called the Norwich Brickearth. In Suffolk it has been observed at Somerleyton, Beccles, Harleston, Woolpit, Boxted, Sudbury, Kesgrave, Hasketon, &c.
Messrs. Wood and Harmer attribute the formation of the marly portion of the Contorted Drift to a discharge of ground-up Chalk from the débouchure of a Glacier that occupied the Chalk country of Cambridgeshire and West Suffolk; the brickearth which fornis the easterly development of the Contorted Drift being due to a river discharge in that part; the two sediments intermingling in the intermediate area, and producing the alternations of marl and brickearth there presented by this formation. The detached masses of the marl were, they consider, introduced into the brickearth portion of the deposit by the agency of bergs, which, breaking from the Glacier and grounding, picked up masses of the marl forming over the sea-bottom in that part of the area. These masses the bergs carried out into the area where the brickearth was accumulating, and grounding again, imbedded them in the brickearth, and even in the subjacent Till and Weybourn Sand, contorting the beds in the process. From detached portions of this marl, which they have found as far south as Claydon, near Ipswich, and Stanstead, near Lavenham, in Suffolk, they infer that this deposit covered the West of Suffolk and Norfolk, but