THE MIRES OF SOUTH WESTERN WESTMORLAND: STRATIGRAPHY AND POLLEN ANALYSIS

Abstract

SummaryThe stratigraphy is described of three examples of the ‘Estuarine Moor’ of Munn Rankin (1910). The mires lie on a deposit of estuarine clay. The conclusion of Erdtrnan (1928), that the oldest layers date from Atlantic times, is confirmed. It is shown that the marine transgression represented by the estuarine clay came to an end early in zone VIIa of the pollen analytical zone scheme.The mires began as fens and reedswamps with some open water at first, and later became converted into raised bogs. At two of the sites there was a transition phase of birch fen wood. The transition from fen to bog took place at different times during the Atlantic and Sub‐boreal periods at the three sites. At two sites a boundary horizon in the Sphagnum peat occurs at the opening of Sub‐atlantic times. The relationships between the stratigraphy at the three sites is shown in Fig. 11.Pollen of Tilia cordata is present in quantity throughout the pollen diagrams, except at the base. The curve for Tilia pollen declines at the opening of zone VIII which has been sub‐divided where the Ulrmus curve declines and the Betula curve begins to rise to a maximum. It is suggested that this maximum of the Betula curve is likely to be due to the colonization by Betula of abandoned fields. At the opening of zone VIIIb, abundant pollen of weeds indicates a period of intense agricultural activity; this period occurs at a time when dryness of the bog surface is indicated by retardation layers at least at two of the sites. Pollen of weeds again becomes abundant as recent times are approached. The indications of early agricultural activity are rather sparse, but pollen of Plantago lanceolata is present at the opening of Sub‐boreal time, and the curves for this pollen tend to increase near the opening of zone VIII.