Geology and Soils
schemes are unlikely to be entirely successful and for conservation reasons should not be carried-
out; impeded drainage is important for many species of plant.
The head deposits and chalky boulder clay almost certainly account, at least in part, for the mosaic
of different grassland types found at Hylands, from the markedly acid in the formal gardens, to the
calcareous till on Writtle Hills. This varying geology is a positive asset to the biodiversity of Hylands
Park.
Alluvial deposits (recent) characterise the low-lying former flood meadow s adjacent to the River
Wid. Hylands has two fields - named Clay Pit Field and Brick Field - presumably the site of a
former brick works, the London Clay providing the raw resource for the bricks. The previously-
mentioned trench also provided evidence, in the form of small fragments of chalk (