32 president's ADDRESS. 



vertical direction. The instances, also, of the transportation of boulderg 

 and smaller stones to higher levels, sometimes large in amount, as in 

 the transference of ' brockram ' from outcrops near the bed of the Eden 

 Valley to the level of Stainmoor Gap, seem to be too numerous to be 

 readily explained by the uplifting action of shore-ice in a subsiding 

 area. Such a process is possible, but I should anticipate it would 

 be rather exceptional. 



Submergence also readily accounts for the above-named sands and 

 gravels, but not quite so easily for their occurrence at such very different 

 levels. On the eastern side of England gravelly sands may be 

 found beneath the chalky boulder clay from well below sea-level to three 

 or four hundred feet above it. Again, since, on the submergence hypo- 

 thesis, the lower boulder clay about the estuaries of the Dee and the 

 Mersey must represent a deposit from piedmont ice in a shallow sea, 

 the mid-glacial sand (sometimes not very clearly marked in this part) 

 ought not to be more than forty or fifty feet above the present Ordnance 

 datum. But at Manchester it reaches over 200 feet, while near Hey- 

 wood it is at least 425 feet. In other words the sands and gravels, 

 presumably (often certainly) mid-glacial, mantle, like the upper boulder 

 clay, over great irregularities of the surface, and are sometimes found, 

 as already stated, up to more than 1,200 feet. Either of these deposits 

 may have followed the sea-line upwards or downwards, but that expla- 

 nation would almost compel us to suppose that the sand was deposited 

 during the submergence and the upper clay during the emergence; so 

 that, with the former material, the higher in position is the newer in 

 time, and with the latter the reverse. We must not, however, forget 

 that in the island of Kiigen we find more than one example of a strati- 

 fied gravelly sand between two beds of boulder clay (containing Scandi- 

 navian erratics) which present some resemblance to the boulder clays of 

 eastern England, while certain glacial deposits at Warnemunde, on the 

 Baltic coast, sometimes remind us of the Contorted Drift of Norfolk. 



Towards the close of the Glacial Epoch the deposition of the boulder 

 clay ceased ' and its denudation began. On the low plateaux of the 

 Eastern Counties it is often succeeded by coarse gravels, largely com- 

 posed of flint, more or less water-worn. These occasionally include small 

 intercalations of boulder clay, have evidently been derived from it, and 

 indicate movement by fairly strong currents. Similar gravels are found 

 overlying the boulder clay in other parts of England, sometimes at 

 greater heights above sea-level. Occasionally the two are intimately 

 related. For instance, a pit on the broad, almost level, top of the 

 Gogmagog Hills, about 200 feet above sea-level and four miles south 

 of Cambridge, shows a current-bedded sand and gravel, overlain by a 



1 Probably deposits of a distinctly glacial origin (such as those near Hessle in 

 Yorkshire) continued in the northern districts, but on these we need not linger. 



