Page:Submerged forests (1913).djvu/66

2nd period of depression	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$	Formby and Leasowe marine beds; human skeleton, bones of horse and red-deer, Scrobicularia, Tellina baltica, Turritella communis, etc.
1st period of elevation	$\scriptstyle {\left.{\begin{matrix}\ \\\ \end{matrix}}\right\}\,}$	Inferior peat- and forest-bed
1st period of depression	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$	Washed drift-sand (apparently no contemporaneous fossils) Boulder clay

It may be an accidental coincidence; but it is noteworthy that both the Mersey and Thames show two main peat-beds separated by marine strata.

The forest exposed on the foreshore at Leasowe (frontispiece) is a particularly good example of these old land-surfaces, and it is often visible. It evidently once formed a wet, peaty flat on which grew swamp plants, brushwood, and some large trees. Parts of it show a perfect network of the rhizomes of Osmunda. This "superior peat and forest-bed" was forming when the sea was only a few feet below its present level. The "inferior peat and forest-bed" probably indicates a drier soil; but it is difficult to get at and requires fuller investigation.

The excavation for an extension of the Barry Docks, in Glamorganshire, exposed in 1895 an interesting succession of deposits, and fortunately a particularly competent observer, Dr Strahan, was on the spot to note them and their exact levels. He also obtained masses of material from each of the beds, and from an examination of the contents