498 Seeley — Gravel and Drift of the Fenlands. 



the Gog-magog, Harston, and Stapleford, indicates that before the 

 gravel was deposited these hills were a continuous table-land. But 

 as the rocks making the gravels are the same as those of the old 

 Boulder-clay, and, as in the case of the Grog-magog, the Boulder- 

 clay itself can be seen a little further down the hill, these seem 

 rather to be examples of reconstructed Boulder-clay, washed of its 

 mud, and converted into gravel. Seeing that these deposits were 

 arranged during upheaval, it may be said as a rule that the oldest 

 beds will be at the higher levels. 



As the country arose from out the icy sea, many Upper Chalklands 

 must have come imder the power of the moving water. And so 

 flints must have been floated out, and sunk or stranded on the low 

 hills. As the land rose higher, these in their turn would be washed, 

 and this would explain the larger proportion of flints at the lower 

 levels. 



Thus by stranding of flints and washing away the mud from 

 Boulder-clay, the coarse gravels may be accounted for. Many con- 

 siderations show that the Boulder-clay was at this time more widely 

 spread. And while the effect of the upheaval has been to wash the 

 Boulder-clay into gravel at high levels, at low levels it must have 

 been swept into holes and valleys, with the addition of much new 

 mud and many local fossils. 



3. Deposits neioer than the Fine Gravel of the Plains. 



Out in the Fen there is little evidence of gravel, except near 

 high places which are built upon ; but the black-peat covers the 

 country like a pall, hiding everything. One section indicates, 

 at Drayton, peat under clay, and gravel under peat. Professor 

 Pryme has told me of other similar sections, and Mr. Marshall, of 

 Ely, has communicated one from near by, which, as typical of all, I 

 will here give. First, he found peat eight feet thick, under which 

 is a clay kno-wm to the workmen as " Buttery-clay." Under this a 

 yew-tree stood erect, well preserved as high as the clay reached, but 

 rotted off in the peat, which was filled with its branches and 

 splinters. The tree stood on a foot of gravel, below which was 

 Kimmeridge-clay. Two similar sections from near Wliittlesea are 

 given by Dr. Porter, in his Geology of Peterborough, in one of 

 which, in place of gravel, was a bed made up of shells of the 

 common edible cockle. But the mammalian remains are chiefly 

 found at the top of the lower bed of peat, and the marine ones in 

 the Buttery-clay, in which are also found Ostrece Cardium Scrobicu- 

 larice, etc. The Marl-bed described by Mr. Hamilton between the 

 upper and lower peats, appears to be a freshwater condition of the 

 Buttery-clay. Half a mile nearer St. Ives than Drayton Gate House, 

 was a section. 



Earth 1 foot. 



Blue-black Clay 1 foot. 



Peat 3 feet. 



Below which was black gravel, from which, at eight feet from the 

 surface, was obtained part of the antler of a red deer. And at 



