Absence of Peat in Areniferous Series.

It is not easy to realise what the conditions were during the formation of the later Terrace Gravels (Barnwell type), and, if it is a fact, why there was not then, as in later times, a marshy peat-bearing area here and there between the torrential deposits of the upper streams near the foot of the hills and the region where the tide met the upland waters. A few plants have been found in the Barnwell gravel but they are very rare in this series. The older Terrace Gravel (Barrington type) might be expected to furnish evidence of the existence of abundant vegetation if we are right in assigning it to about the age of the peaty deposits overlying the Weybourn Crag. But at present we have no evidence of any such deposit in the Cambridge gravels.

Although there are great masses of vegetable matter formed in the swamps of tropical regions, peat is essentially a product of northern climes. Pliny[4] evidently refers to peat as used in Friesland but not as a thing with which he was familiar.