II. On a Section of the Lower Chalk near Ely

Extract

Ely stands on a hill extending somewhat beyond the city as a ridge to the north; and a mile north-east of the Cathedral, at a spot variously named Roslyn or Roswell Hole, its flank is reached at a well-known pit, where the Kimmeridge Clay is dug for mending the river-banks; and the excavation shows some Boulder-clay and Chalk. What the relative positions and relations of these latter deposits may be has been long disputed; some holding that the Chalk is there in sitû, let down by a fault; others maintaining that it is merely such a drifted mass, included in the Boulder-clay, as those which form so strange a feature in the Drift of the Norfolk Coast.† Professor Sedgwick has long been convinced that this latter view is a groundless hyothesis; for when the railway was made from Ely to Lynn, it exposed at about 100 yards off a section showing Kimmeridge Clay and Chalk side by side, and Boulder-clay between them; so the conclusion inevitably followed that there had been a great fault; letting down the Chalk for at least two or three hundred feet. This section was still to be seen in the spring of 1860, when I examined it. The faulted faces of both stratified formations were perfectly erect, parted by a column of Boulder-clay, some twelve feet wide, which from a distance looked like a basaltic dyke.