ALLUVIAL COVERING. S3 



stagnant ponds. The authors also found here an imperfect valve of 

 a fresh water muscle. The marl in some parts is so indurated as to 

 have nearly acquired the hardness of limestone; and, in like man- 

 ner, a few portions of the peat approach to the state of coal. Over 

 these beds is the highest part of the alluvium, consisting of coarse 

 clay or clayey marl, with vegetable soil. 



Similar patches are found in the cliffs between Cowden and 

 Hornsea, at a great elevation above the sea, and only a few feet 

 below the surface. In one of these exposed bogs, near Cowden, an 

 efflorescence of sulphate of iron was observed in several spots, on 

 the face of the cliff. Patches of peat bog may also be observed be- 

 tween Hornsea and Bridlington ; but the most remarkable instance 

 occurs opposite Skipsea. Hei'e a large morass, several feet in thick- 

 ness, is exposed to the sea, containing as usual decayed trees, and 

 other vegetable remains. The alluvial covering over it is in general 

 very slight, and in some parts the peat reaches the surface. This 

 morass cannot be called submarine, for though the sea washes tlie 

 lower part of it at high water, it does not cover the upper part. 

 Here, as in the cliff at Grimston Garth, the authors discovei-ed the 

 shells of a fresh water muscle, apparently the mya pictoriim. 



From these facts, compared Avith others which are yet to be 

 stated, we arrive at the conclusion, that these supposed remains of 

 submarine forests are only the bottoms of fresh water lakes, or meres, 

 Avhich the sea has broken into, and drained. Wherever the country 

 has abounded with wood, and this was once the case with a great 

 part of Britain, the bottoms of meres or marshes contain vast quan- 

 tities of these decayed trees and vegetable substances. They are 

 found in the bottom of Hornsea mere, wherever it has been dug into; 

 and were the sea to break throvigh the barriers of that mere, the same 

 kind of peat bog would be exposed there as we see in the spots al- 

 ready mentioned: nay, we should find over the peat a stratum o^ 



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