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IV] mud. It is fissile and very hard when dry, and in it are scattered a certain number of fairly well-preserved seeds, principally belonging to the bog-bean. Other recognisable plant-remains are not abundant. They consist of rare willow-leaves, fragments of birch-wood and bark, pieces of the scalariform tissue and sporangia of a fern, and moss, and, curiously enough, of groups of stamens of willow-herb with well-preserved pollen-grains, though the whole of the rest of the plant to which they belonged had decayed.

The material is exceptionally tough, and is very difficult to disintegrate. In order to remove the structureless humus which composed the greater part of the peat, we found it necessary to break it into thin flakes and boil it in a strong soda solution for three or four days. Afterwards the material was passed through a sieve, the fine flocculent parts being washed away by a stream of water, the undecomposed plant remains being left behind in a state for examination. These remains were mixed with a large amount of shreds of cuticle, etc., but recognisable leaves were not found in the washed material.

The general result of our examination is to suggest that the deposit comes from the middle of some vast fen, so far from rising land that all terrigenous material has been strained out of the peaty water. The vegetation, as far as we have yet seen, consists exclusively of swamp species, with no admixture of hard-seeded