542 REPORT—1904. 
sion. The Upper and Lower Kimmeridge Clay are found at Ely and in the neigh- 
bourhood of that city. 
Of Cretaceous rocks the Lower Greensand is well seen near Gamlingay. The 
old phosphate workings of Wicken are now closed. The Gault is seen in many 
exposures. Most of the sections exhibit Lower Gault, but Mr. Fearnsides has 
recently detected the Upper Gault in the Barnwell brick-pit. The basal member 
of the Chalk, the well-known Cambridge Greensand phosphatic seam, lies uncon- 
formably upon the Gault. It is succeeded by various divisions of the Chalk up to 
the zone of Micraster. 
The glacial deposits consist chiefly of the chalky boulder clay ; the great boulder 
at Ely is of interest. 
The Pleistocene gravels include the plateau gravels on the chalk hills and the 
well-known mammaliferous gravels forming terraces on the valley-sides. The 
March marine gravels are usually correlated with the gravels of one of these 
terraces. 
Alluvium is found on the valley-bottoms, and in the fenland peat occurs with 
intercalated patches of Scrobicularia clay. The peat contains the fauna of 
Neolithic and later times. 
2. The Great Eastern Glacier. By F. W. Harmer. 
This name is proposed for the great ice-stream, the moraine of which, the 
chalky Boulder Clay, covers an area of more than 5,000 square miles in the East 
of England, frequently attaining a thickness of more than 100 feet. 
As far back as 1858, Trimmer, a pioneer in glacial investigation, had pointed 
out that the county of Norfolk had been twice invaded by ice, first from the 
North Sea and then from the west, the resulting detritus in the one case being 
characterised by igneous blocks, some of them of Scandinavian origin; and in the 
other by a predominance of Jurassic material. The first invasion is represented 
by the Cromer Till and the contorted Drift of the Norfolk coast; the second, 
which does not occur in north-east Norfolk, by the chalky Boulder Clay, the 
subject of the present paper. 
The region covered by the latter deposit, which extends over a great part 
of the eastern counties of England, has a palmate outline, its lobes, which 
radiate from the great depression of the Lincolnshire and Cambridgeshire Fens, 
being of unequal length, The latter region was not only the centre whence 
the chalky Boulder Clay was distributed, but also the quarry out of which was 
excavated the enormous mass of Jurassic material forming to a great extent the 
matrix of this deposit. 
The present physiographical features cf the East of England closely resemble 
those which obtained in glacial times, the Drift deposits not only covering the 
plateaux between the valleys in which the rivers of the district now run, but 
descending into them, sometimes to below sea level. Hence by the study of the 
existing contours, aided by that of well-borings, it is possible to obtain a general - 
idea of the preglacial topography by which the movements of the ice must have 
been influenced. 
Although the erratics of the chalky Boulder Clay are more or less of a similar 
character over a wide area, indicating that it was distributed from a common 
centre, its predominant character varies in different districts, in accordance with 
that of the strata over which the ice moved. The matrix of the Boulder Clay of 
south Norfolk and north Suffolk, for example, has been largely derived from the 
Kimmeridge Clay. Over this region, which formed in glacial times a shallow 
trough running east and west, corresponding with the present depression of the 
basins of the Little Ouse and the Waveney, as well-as with the gap in the Chalk 
escarpment between Swaffham and Newmarket, the ice evidently poured in great: 
volume, planing down the surface of the Chalk and carrying its Kimmeridgian 
material fifty miles to the east from its original source in the Fen basin. On the 
other hand, although the Fen ice was sufliciently thick to enable it to overflow 
