Geoscience Reference
In-Depth Information
3.2 Geological Classification
Although the research carried out by Harmer on the East Anglian Crags presented
in this topic employ geological terms that were in use during his time, the stra-
tigraphy of the Red Crag and the Norwich Crag have now been assigned to the
Pleistocene rather than Pliocene Epoch. In 1948 the International Geological
Congress recommended that the base of the Red Crag should be adopted as the
beginning of the Pleistocene Epoch in Britain, with only the Coralline Crag
remaining in the Pliocene. Further criteria for placing the Pliocene-Pleistocene
boundary between the Coralline and Red Crags, including the presence of a
stratigraphical break, marked increase in the proportion of northern forms of
marine molluscs (indicative of a refrigeration of the climate) and the first arrival of
elephant and horse were presented in 1957 (West
1957
). However, the former
classification, which included all of the East Anglian Crags within the Pliocene, is
employed in this volume in order to retain continuity with the geological studies
undertaken by Harmer.
3.2.1 Introduction
Harmer was very much a 'hands-on' geologist who based his research on extensive
studies in the field. A series of unpublished notebooks dating from 1865 provide
evidence of Harmer's activities in geological field work; further notebooks contain
fragments from Searles V. Wood, Junior's field work and references to Geological
Survey Memoirs. Other unpublished material illustrates Harmer's wide-ranging
interests in earth science such as the nomenclature of geological formations, a
lecture on the geology of Norfolk, Pleistocene deposits of East Anglia; miscella-
neous notes on glacial geology, boulders and various borings; notes by Professor
Kendall; miscellaneous survey memoirs referring to occurrences of boulder-clay;
notes and discussion of a paper by Professor P.G.H. Boswell; notes on the Crag
formations; notes on the Cromer Forest Bed Series of East Anglia; and letters to
fellow geologists such as J. Geikie, Kitchen, Allen and H.B. Woodward.
3.2.2 Pliocene and Pleistocene Deposits of East Anglia
Harmer made many field excursions to geological sites in East Anglia and was
never happier than when demonstrating in situ the varied deposits of the region to
interested groups. For example, on 9-14 July 1903 he led a field excursion to
Cromer, Norwich and Lowestoft. In an account published later in the Proceedings
of the Yorkshire Geological Society he wrote:
