480 PHILOSOPHICAL TRANSACTIONS. [ANNO 1799. 



woods evidently exist in these islets, of some of which we found the leaves in the 

 soil ; but our present knowledge of the comparative anatomy of timbers, is not so 

 far advanced as to afford us the means of pronouncing with confidence respecting 

 their species. In general, the trunks, branches, and roots of the decayed trees, 

 were considerably flattened ; which is a phenomenon observed in the Surtarbrand 

 or fossil wood of Iceland, and which Scheuchzer remarked also in the fossil wood 

 found near the lake of Thun, in Switzerland. The soil to which the trees are 

 affixed, and in which they grew, is a soft greasy clay ; but, for many inches above 

 its surface, the soil is entirely composed of rotten leaves, scarcely distinguishable to 

 the eye, many of which may be separated, by putting the soil in water, and dexter- 

 ously and patiently using a spatula, or a blunt knife. By this method I obtained 

 some perfect leaves of ilex aquifolium, which are now in the herbarium of Sir Jos. 

 Banks; and some other leaves which, though less perfect, seem to belong to some 

 species of willow. In this stratum of rotten leaves, we could also distinguish several 

 roots of arundo phragmites. 



These islets, according to the most accurate information, extend at least 12 miles 

 in length, and about a mile in breadth, opposite Sutton shore. The water without 

 them, towards the sea, generally deepens suddenly, so as to form a steep bank. 

 The channels between the several islets, when the islets are dry, in the lowest ebbs 

 of the year, are from 4 to 1 2 feet deep ; their bottoms are clay or sand, and their 

 direction is generally from east to west. A well dug at Sutton, by Josh. Searby, shows 

 that a moor of the same nature is found under ground, in that part of the country, 

 at the depth of 16 feet; consequently, very nearly on the same level with that which 

 constitutes the islets. The disposition of the strata was found to be as follows : 



Clay J 6 feet- 

 Moor, similar to that of the islets from 3 to 4 ditto. 



Soft moor, like the scoweringsof a ditch bottom, mixed with shells and silt 20 ditto. 



Marly clay 1 foot. 



Chalk rock from 1 to 2 feet. 



Clay 31 yards. 



Gravel and water j the water has a chalybeate taste. 

 In order to ascertain the course of this subterraneous stratum of decayed vegeta- 

 bles, Sir Jos. Banks directed a boring to be made, in the fields belonging to the 

 r. s., in the parish of Mablethorpe. Moor, of a similar nature to that of Searby's 

 well, and of the islets, was found, very nearly on the same level, about 4 feet thick, 

 and under it a soft clay. 



The whole appearance of the rotten vegetables we observed, perfectly resembles, 

 according to the remark of Sir Jos. Banks, the moor which, in Blankeney fen, and 

 in other parts of the East fen in Lincolnshire, is thrown up in the making of banks ; 

 barks, like those of the birch tree, being there also abundantly found. This moor 

 extends over all the Lincolnshire fens, and has been traced as far as Peterborough, 

 more than 60 miles to the south of Sutton. On the north side, the moory islets, 

 according to the fishermen, extend as far as Grimsby, situated on the south side of 



