Pollen analysis
The most complete fossil record of plant life in the Norwich Crag is provided by evidence from the Ludham research borehole. Pollen analysis in association with foraminiferan evidence allowed the identification of pollen assemblage biozones and consequent designation of five biostratigraphic stages, of which three (Thurnian, Antian and Baventian) are correlated with the Norwich Crag. The Thurnian was identified as a glacial stage with an oceanic heath type of vegetation; the Antian with temperate mixed coniferous / deciduous forest including "Tsuga" (hemlock) and "Pterocarya" (wingnut); the Baventian, a glacial stage more severe than the Thurnian, with the return of oceanic heath. Further work on Norwich Crag sediments at Bramerton, Norfolk, allowed a Bramertonian stage to be identified, characterised by temperate forest with "Quercus", "Carpinus" and "Alnus". Correlation was made with the pollen assemblage from Chillesford. Specimens of fossil wood have occasionally been found, for example pyritised pine and oak at Holton.