On the Position and General Characters of the Strata exhibited in the Coast Section from Christchurch Harbour to Poole Harbour

Abstract

I have on former occasions described the eocene strata of White-cliff Bay and of Alum Bay*. The sections of these two localities show in a remarkable manner the changes there undergone, in the comparatively short distance of twenty miles, by the series of sands and clays forming the Bracklesham Bay beds, and included between the London clay and the Barton clay. I also gave the commencement of the section of the Barton clays at Barton, to show their connection with the upper part of the section at Alum Bay. I have recently had the opportunity of further examining the coast-sections from Barton Cliff to Poole Harbour, with a view to continue the sequence of superposition lower in this more westward portion of the series. This part of the coast was described by Sir Charles Lyell in a paper read before this Society in March 1826. I need not therefore enter into a detailed description of the strata, but will confine myself to the question of the exact position which they bear with reference to the Barton clay, and to a few general observations on their physical conditions. The progress made by the sea in the destruction of the cliffs has also, I believe, brought to light some new features. In the first place I have, I think, obtained evidence of the existence of the Barton clays to the westward of Christchurch Harbour ; consequently the section downwards from them, which I had discontinued at Muddiford, can now be taken up