The Developmental History of Blelham Tarn (England) as Shown by Animal Microfossils, with Special Reference to the Cladocera

This purpose of this investigation was to elucidate the developmental history of Blelhaii Tarn (English Lake District) fromn the sub-fossil remains of Cladocera, midges and neorhabdoceles in the sediments. Blelham Tarn is a lake about 50 ha area and roughly ovoid in shape. It lies at an altitude of 41 in in the Winderniere Valley about one mile northwest of Lake Winderrnere. During September 1963 a core (hereafter designated core A) was taken by Dr. Winifred Tutin of Leicester University and myself at a site somte 45 in northwest of the western shore with a Cambridge core sampler. A second core (designated core B) from the deep water sediments had been taken previously by the staff of the Freshwater Biological Association during January 1962 using the Mackereth core sampler. The pollen analysis on this latter core has been published by Penningtoii (Mrs. W. Tutin) (1965). Mrs. Horewood, also of Leicester University, has completed a pollen diagram of the Late-glacial section from core A, hut this is not as yet published. Palaeolimnology from the zoological point of view began as an offshoot of palynology and investigations of lake sediments by geographers. The classic works of von Post (1862) and Lundquist (19224, 1927) on lake sediment types and sediment succession sowed the seed of a new era in liniinology. Messiatsev (1924) was perhaps the first to engage in ally extensive work on the identification of animal remains in lake sediinents, but this was only qualitative in nature. Later Gains (1927) first used animal remains as typological indicators in lake sediment succession. Also in 1927,