225 
with, the drainage, partly by affording a pabulum of decom- 
posing vegetable matter, congenial to the growth of mosses 
and other Peat-forming plants. The heart-wood of the fir 
trees is very hard and tough, and in excellent preservation, 
but the tool marks are soon lost on exposure. There are large 
woods of Scotch fir in the East Riding, growing on the wet 
heathy surface of the same bed of Sand, and I am of opinion 
that these firs may be lineal descendants of those which 
anciently inhabited the district ; if so, the Scotch fir must be 
considered a native here. The forest bed may be traced from 
Eastoft to Long Drax, thus crossing the Aire, and from 
Thorne to Q-ooIe, where stumps of trees may be seen in the 
river-bed between tide marks ; but I do not know any 
instance of its occurring east of the Ouse. It is puzzling to 
find in the Hook Bridge section (Section 4) a bed of 
Peat seven foot six inches thick, 18 inches below the 
bottom of the river, i.e.^ some 12 feet below the level 
of that at Goole. I am inclined, however, to suspect 
that this must be an older bed, occupying a hollow scooped 
out in the clay, which here is only 18 inches thick; no 
trees are mentioned. At Reedness (Section 3), a bed of Peat, 
nearly 12 feet thick, with fragments of rotten wood, occurred 
at the depth of 30 feet, and at Rawcliffe (Helliwell's Brewery, 
Section 9), six inches of Peat were found at a depth of 47 feet ; 
these beds must have occupied hollows in the clay at the time 
when the land stood at a higher level than at^ present. At 
Askern and at Monk Fryston, close to the edge of the 
Magnesian Limestone, and filling up hollows in the clay, are 
superficial Peaty deposits containing abundance of shells. At 
each place there is a swampy pool, no" doubt tlie remains of a 
large one which at some time filled up the whole area 
occupied by the shelly Peat ; both these pools are fed by 
mineral springs — that at Askern by the stream from the Spa 
well; that at Monk Fryston by the spring which supplies 
