carbonaceous matter. Iron must play an important part. There is in the Sedgwick Museum part of the trunk of a Sussex oak which had grown over some iron railings and extended some eight inches or more beyond the outside of the part which was originally driven in to hold the rails. Mr Kett came upon the buried iron when sawing up the tree in his works and kindly gave it to me. From the iron a deep black stain has travelled with the sap along the grain, as if the iron of the rail and the tannin of the oak had combined to produce an ink. The well-known occurrence of bog-iron in peat strengthens this suggestion. An opportunity of observing this enveloping growth of wood round iron railings is offered in front of No. 1, Benet Place, Lensfield Road.

The trees in the Fens often lie at a small depth and when exposed to surface changes perish by splitting along the medullary rays.

It is not clear how long it takes to impart a peaty stain to bone, but we do find a difference between those which are undoubtedly very old and others which we have reason to believe may be more recent. Compare the almost black bones of the beaver, for instance, with the light brown bones of the otter in the two mounted skeletons in the Sedgwick Museum.

  Marl.

"Marl," as commonly used, is Clay or Carbonate of Lime of a clayey texture or any mixture of these.

Beds of shell marl tell the same tale as the peat. Shells do not accumulate to any extent in the bed of a river. They are pounded up and decomposed or rolled along and buried where mud or gravel finds a resting place. Only sometimes, where things of small specific gravity are gathered in holes and embayed corners, a layer of freshwater shells may be seen.

But to produce a bed of pure shell marl the quantity of dead shells must be very large and the amount of sediment carried over the area very small, while the margin of the pond or mere in which the formation of such a bed is possible must have an abundant growth of confervoid algae and other water plants to furnish sustenance for the molluscs. Shell marl therefore suggests ponds and meres. Of course it must be borne in mind that in a region of hard water, such as is yielded in springs all along the outcrop of the chalk, there is often a considerable precipitation of carbonate of lime, especially where such plants as Chara help to collect it, as the Callothrix and Leptothrix help to throw down the Geyserite.

These beds of white marls, whether due to shells or to precipitation, are thus of great importance for our present enquiry as they throw light on the history of the Fens.

We should have few opportunities of examining the marl were it not for its value to the agriculturist. As it consists of clay and lime, it is not only a useful fertiliser but also helps to retain the dusty peat, which when dry and pulverised is easily blown away. Moreover, as the marl occurs at a small depth and often over large areas, it can commonly be obtained by trenching on the ground where it is most wanted.

  The Wash.

We have now carried our examination of the Fen Beds up to the sea, but to understand this interesting area we must cross the sea bank and see what is happening in the Wash. There is no peat being formed there, nor is there any quantity of drifted vegetable matter such as might form peat. There are marginal forest beds near Hunstanton and Holme, for instance, and it is not clear whether they point to submergence or to the former existence of sand dunes or shingle beaches sufficient to keep out the sea and allow the growth of trees below high water level behind the barrier, such as may be seen at Braunton Burrows, near Westward Ho, or at the mouth of the Somme. What is the most conspicuous character of the Wash is that the upland waters, now controlled as to their outlet, keep open the troughs and deeps while tidal action throws up a number of shifting banks of mud, sand and gravel, many of which are left dry at low water. Along the quieter marginal portions fine sediment is laid down, and relaid when storms have disturbed the surface. On these cockles and other estuarine molluscs thrive. Before the sea banks were constructed these tidal flats extended much further inland.

  Littleport District.

In the light of this evidence let us examine the Fen Beds east of Littleport, a district of great interest not only from its geographical position in relation to the Fens but also from the remains recently discovered there.

Looking north and west there is no high ground between us and the Wash. If we could sweep out the soft superficial deposits and abolish the sea banks the tide would still ebb and flow over the whole area.

If we look north and east we see the high ground stretching from Downham Market to Stoke Ferry and sweeping round to the south by Methwold and Feltwell and the islands of Hilgay and Southery, thus enclosing a great bay into which the Wissey on the north and the Brandon River on the south deliver the waters collected on the eastern chalk uplands.

The island known as Shippea Hill marks the trend of an ancient barrier blocking the northward course of the river Lark. (Fig. 6, p. 29.)

Here, then, it seems probable that we might find evidence of a local change from the conditions we now see in the Wash and those which have resulted in the formation of the Fens.

  Buttery Clay.

In deep trenching in the Fen between Littleport and Shippea Hill in order to obtain clay for laying on the peaty surface a very fine unctuous deposit was found at a depth of four or five feet. The overlying Fen Beds were chiefly peat with lenticular beds of white marl and grey clay, obviously laid down from time to time in small depressions in the surface of the peat. This marl was often largely made up of, or was at any rate full of, freshwater shells but sometimes showed evidence of having been gathered on the stems of Chara which on perishing have left small cylindrical hollows penetrating the partly consolidated marl. Under these beds of peat and marl there was the unctuous clay, which is sometimes referred to as the Buttery Clay. It is an estuarine deposit like that mentioned above as occurring in the Wash off Heacham, for instance. It contains shells of Cardium edule, Tellina (Tacoma) balthica, Scrobicularia piperata, and other estuarine shells, some of which had the valves adherent or rather adjoining, for the ligament had perished. Mrs Luddington has in her collection the bones of the Urus, Wild Boar and Beaver, obtained from the peat above this Buttery Clay.

On the other or south-western side of Shippea Hill, which is an island of Kimmeridge Clay, we get further into the embayed and isolated portions of the Fen and we find more peat in proportion to the other deposits although it is very thin. There are still small lenticular beds of white marl similar to that nearer Littleport and the peat rests upon Buttery Clay of unknown thickness. In this part, however, no shells have yet been noticed. Near Shippea Hill the peat has recently been trenched with a view to obtaining clay with which to dress the surface of the peat and it was here, at a depth of four feet from the surface and four inches above the Buttery Clay, that the human bones described below (pp. 27-35) were found.

  The Age of the Fen Beds.

Now we may enquire what are the limits within which we may speculate as to the age of the Fen Beds.

These Turbiferous deposits all belong to one stage, though it may be one of long duration. They are sharply separated from the Areniferous deposits, i.e. the sands and gravels of the terraces and spurs which always pass under and, in fairly large sections, can always be clearly distinguished