Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/610

 division of the Bed Crag ; that the Chillesford series filled up and levelled the irregular surface of the Red and Coralline Crags, over the highest portion of both of which it extends ; that reefs of the Coralline Crag divided the Red-Crag sea into different areas, with local variations in the distribution of the Molluscan fauna; and that the area north of Aldborough was not only separated from the more open sea to the south, but was also more subject to the influence of fresh water, the beds at once being more littoral and containing a larger number of freshwater Testacea. The Chillesford Clay was traced to Southwold, where it holds the same relation to the shelly sand-beds as it does in the Chillesford and Sudbourne districts.

Beyond the few pits in the neighbourhood of Southwold and Wangford there are no sections of the crag in north Suffolk. On the borders of Norfolk, however, we reach a section of great interest, which was discovered a few years since by Mr. Rose, of Yarmouth. It is in a brick-pit in the parish of Aldeby, at a distance, by road, of four miles from Beccles.

The section is as under : —

Fig. 27.— Pit at Aldeby.

feet.

a. Valley-gravel 2 to 4

3. Chillesford clay 5 to 7

3'. Light-coloured sands, with seams of fine gravel and of shells 6

A boring has been carried through sands 10 feet deeper, when the tool was stopped by a bed of gravel.

The Chillesford Clay is well developed, with its usual characters of a laminated grey micaceous clay ; but no shells have been found in it here. Large flints, little worn, and fragments of wood are occasionally met with ; and Mr. Dowson informs me that he found in the upper part of the clay the condyle of the femur of Elephant. The marked feature of the section is the occurrence of the Crag shells, not, as usual, with the larger portion in a comminuted state, but entire and with a number of double shells, many in the same position as when living. Occasionally large masses of flint are found in the sand. I saw one which weighed 3/4 cwt. ; and adhering to it were numerous basal plates of the Balanus porcatus. The undisturbed condition of the beds offers an unusually favourable opportunity of investigating the fauna of this part of the series free from the introduction of any foreign element, — an opportunity of which Mr. W. M. Crowfoot, and Mr. E. T. Dowson, of Beccles, have taken excellent