Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/633

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but still leaving land in the near vicinity. Prom this land wood and freshwater testacea, and some mammalian remains were carried down into the great beds of shingle forming off the coast in a sea in which still lingered some of the Crag Mollusca. At the same time a portion of the old forest land as well as of the marine clays which preceded it were denuded. These sands and shingle are of much greater extent than the forest-area, and spread over all East Norfolk, Suffolk, Essex, and beyond. The main feature of this deposit is the presence of flint pebbles with a considerable proportion of white and pink quartz pebbles and a few pebbles of slate, together with some rolled fragments of Greensand chert. On the table-land above the Meuse, in Belgium, there is a gravel of a very similar character ; and I think it not improbable that some old river traversing the Ardennes may then have brought down into this Crag- sea area the old slate, quartz, and quartzite pebbles found so abundantly in the Westleton shingle, while other streams from the south or south-west may have drifted in the chert from the Lower Greensand and the mass of flint pebbles from the Chalk *.

The relation of the Crag sea of Belgium with that of the southeast of England has been the subject of frequent inquiry. Taking the revised lists of M. Dewalque and those at the end of this paper, the following results are arrived at respecting the species common to the several deposits.

Numerical Distribution.

Total. Sables gris. Sables jaunes. Sables noirs.

Norwich Crag 155 60 68 24

Suffolk or Red Crag 273 122 138 61

Corraline Crag 316 133 135 98


Proportional Distribution.

Sables jaunes. Sables gris. Sables noirs.

Norwich Crag 43.9 38.7 15.5 per cent.

Suffolk or Red Crag 50.5 44.7 22.3 " "

Corraline Crag 42.7 42.4 31.0 " "

This shows a more marked connexion between the upper or Red and Norwich Crags and the Sables jaunes and gris, forming the Systeme Scaldisien of Dumont, than was before noted ; whilst the lower or Coralline Crag seems to hold a place intermediate between these beds and the Sables noirs, or the Systeme Diestien of Dumont.

Such, then, are some of the changes which mark the epoch of the

  • I have also met with rolled fragments of silicified wood, like that which I

have found in situ in the Woolwich and Reading Eocene series of Kent.