Birds — Bed of Chalk- jlints near Spa. 501 



Summary. 



1. THe brown Bounder-clay corresponds ■with, tlie brown Clay of 

 the Eastern counties, and is oldest. 



2. Then the hill gravel, the blue Bonlder-clay, and perhaps the 

 shell bed of March corresponds to the contorted drift. 



3. As elevation progressed, the Fenlands would become one great 

 fiord, ramifying at the Cambridge end up the southern valleys in 

 the Chalk. First tbe coarse gravels of low levels were formed, and 

 finally, during a long period — for the flints are wonderfully worn — 

 the fine gravel of the plains. After which the country was elevated, 

 and the sea denuded the superficial beds and retired. This corres- 

 ponds to the Upper Boulder-clay and coarse gravel of the Norfolk 

 section. 



4. Now rivers cut their channels, and there commenced luxuriant 

 vegetable growth, which corresponds with the excavation of the 

 Mundesley river and the Mundesley peat. 



5. Then a depression, during which was formed the Buttery-clay 

 of the Fens. This corresponds with the Upper Sands and Gravel of 

 Mundesley. 



6. And, finally, comes the second peat and the present state of 

 nature. 



I believe this succession is true for a far larger area than the 

 Fenlands, perhaps for all Great Britain. 



VI. — On a Bed of Chalk-flints near Spa. 

 By J. A. Birds, Esq. 



THE fashionable Belgian watering place, Spa, is situated 1000 feet 

 above the sea, in the centre of a circle of hills called the High 

 Moors (Les Hautes Fauges), a wild and desolate tract covered with 

 peat-bogs and heaths, themselves some 600 to 800 feet above the 

 town. Immediately above Spa, and opposite to it, there are two 

 other distinct hills, of lesser height, the limits of which are definitely 

 marked out by streams or deep valleys, and these, together with" the 

 " High Moors" and their rock, constitute the leading geographical 

 features of the immediate neighbourhood. 



The dhief geological constituents of the district consist of Silurian 

 Bhenan, Devonian, and Carboniferous rocks, together with the allu- 

 vium of the Wayai,^ and the diluvium descending to it from the 

 summits of the High-Moors Hills. But, upon the crest of the latter, 

 a little to the right of the road from Spa to the village of Francor- 

 champs, there is a thin bed of chalk flints, of perhaps a mUe square 

 in extent, strewed over the peat or embedded in it, forming one of 

 the most interesting geological phenomena in the neighbourhood. 



The bed, as far as I am aware, is completely isolated, the nearest 

 cretaceous deposits beiag those of Maestricht and Aix la Chapelle, 



1 The "Wayai is a small stream, having its source in the Moors eastward of Spa, 

 ■which, after flowing by the town, turns sharply to the north and continues its coiu'se 

 in a line parallel with the railway to the Vesdre, a tributary of the Meuse. 



