The geology and fossils of the Burnham Chalk Formation (Upper Cretaceous, Upper Turonian stage) of North Ormsby, Lincolnshire

John P Green (UK) The large, disused quarry at North Ormsby [O.S. grid ref. TF2893], north of Louth in Lincolnshire, displays an important sequence of beds of the Burnham Chalk Formation (Upper Cretaceous, Upper Turonian stage) and, at present, constitutes the best exposure of the beds in the county. Similar beds exposed at Ulceby Vale Pit [TA104133] in North Lincolnshire have described in terms of both stratigraphy and palaeontology, by Wood (1992) and, more recently, by Hildreth (1999, and in press). Fig. 1. North Ormsby disused quarry; an important sequence of beds of the Burnham Chalk Formation. The North Ormsby section was measured and described in stratigraphical terms by Wood and Smith (1978), although little information on the macrofauna was published. Hill (1902) was the first to identify the S. plana biozone of the Burnham Chalk Formation in this area, and Rowe (1929) provided an admirable macrofaunal list in his account. Therefore, my aim is to build on the work of previous authors, and place the recorded macrofossils in a stratigraphical context. In addition, Wood and Smith (1978) established important flint and marl marker horizons for the chalk of Lincolnshire and Yorkshire, and these shall be referred to in this account. Fig. 2. Closeup of the Burnham Chalk Formation. The Burnham Chalk, as exposed at this locality, consists in general terms of thick bedded chalk, interbedded with marl seams and marl layers, and beds of predominantly tabular and semi-tabular flint bands. About halfway up the sequence, above the level of … Read More