in diameter; they retained a whitish colour like touch wood, and were softer than the adjacent earth or moor log. The moor log appeared at about three or four feet under the marsh ground, and differed in thickness at different parts; at Deptford it was six feet thick; at Woolwich Reach, opposite the ballast wharf, it was between seven and eight feet thick; its thickness as well as its breadth gradually increasing down the river. Beneath the moor log was a stratum of blue clay, and under this gravel and sand. Stags horns were likewise found in different places, a little above the vein of moor log.
Mr. Derham's account of the Dagenham marsh land (Phil. Trans. 1710, p. 478), affords the following particulars in addition to those given by Capt. Perry.
The stumps and roots of many trees were found in the same posture in which they grew, situated in a soil consisting of a black oozy earth, full of the roots of reeds; the tops of these stumps were so worn that it could not be ascertained whether the bodies had been cut off by the ax, or broken by natural violence. The bodies themselves lay horizontally on the surface of the oozy earth, in confusion, but a northerly direction seemed most prevalent. They appeared almost all of them to have been alder, though at first they were supposed to be yew. Over the trees lay a covering of grey mould, of the same nature with the sediment of the Thames at this day, varying in thickness from seven to twelve feet. Mr. Derham mentions the names of the following places in which he noticed traces of this subterranean forest. Dagenham, Havering, Rainham, Wennington, Purfleet, West Thorrock.
It happened a few years ago that in cutting the canal and basins in the Isle of Dogs, a subterranean forest containing hazel nuts, with
