146 Dr. Correa de Serra on a submarine Forest , 
equinoctial full moon, when the lowest ebbs were to be ex- 
pected, we went in a boat, at half past twelve at noon, and soon 
after set foot upon one of the largest islets then appearing. Its 
exposed surface was about thirty yards long, and twenty-five 
wide, when the tide was at the lowest. A great number of 
similar islets were visible round us, chiefly to the eastward and 
southward ; and the fishermen, whose authority on this point 
is very competent, say, that similar moors are to be found along 
the whole coast, from Skegness to Grimsby, particularly off 
Addlethorpe and Mablethorpe. The channels dividing the islets 
were, at the time we saw them, wide, and of various depths ; 
the islets themselves ranging generally from east to west in 
their largest dimension. 
We visited them again in the ebbs of the 20th and 21st; 
and, though it generally did not ebb so far as we expected, we 
could notwithstanding ascertain, that they consisted almost 
entirely of roots, trunks, branches, and leaves of trees and 
shrubs, intermixed with some leaves of aquatic plants. The 
remains of some of these trees were still standing on their 
roots ; while the trunks of the greater part lay scattered on the 
ground, in every possible direction. The bark of the trees 
and roots appeared generally as fresh as when they were grow- 
ing ; in that of the birches particularly, of which a great quan- 
tity was found, even the thin silvery membranes of the outer 
skin were discernible. The timber of all kinds, on the contrary, 
was decomposed and soft, in the greatest part of the trees ; in 
some, however, it was firm, especially in the knots. The people 
of the country have often found among them very sound pieces 
of timber, fit to be employed for several ceconomical purposes. 
The sorts of wood which are still distinguishable are birch. 
