30 DESCRIPTION OF THE STRATA. 



choaked up; but by diligent search were again recovered, rising-, 

 most probably, from under the mass of clay that had overwhelmed 

 them, or percolating through fissures or crevices in its substance. 

 The virtues of these waters are no doubt owing to the nature of the 

 minerals through which they pass. Their principal ingredient is 

 sulphate of magnesia, which is most abundant in the south well. 

 They also contain muriate of magnesia, carbonate of lime, sulphate 

 of lime, vdth a small portion of carbonate of iron, and of muriate 

 of natron.* 



Before we take our leave of the alluvial covering, it will be pro- 

 per to advert to those remains of peat bogs or morasses, which are 

 found under some of the alluvial beds, and which in many instances 

 occur below the level of the sea at high water, and are hence de- 

 scribed as the remains of submarine forests. 



An extensive morass of this description exists on the banks of 

 the Humber in the vicinity of Hull, where it forms a sort of stratum 

 about three feet thick, consisting of moor earth, decayed trees, and 

 other vegetable substances. Similar remains have been found at 

 Withernsea, Homsea, and some other parts of the Holderness coast; 

 and it is well known, that they have also been observed in great 

 abundance on the southern banks of the Humber, and on a great 

 part of the shores of Lincolnshire. The same phenomenon has been 

 met with on the banks of the Esk in Whitby harbour, particularly 

 in digging for the formation of docks ; and may be seen also on the 

 Durham shore, between Hartlepool and Seaton. 



In these bogs or morasses are found immense quantities of trees, 

 of various sizes, with bi'anches, leaves, roots, &c. The trees are of 

 such kinds as ai-e known to be natives of this country, as oak, ash, 

 fir. hazel, holly, beech, willow, &c. The fruits of some of them,. 



* See Hioderwell's Hist, of Scarborough, 2nd Edit. p. 306. 



