SUBMERGED FORESTS. 52$ 



Peat beds vary in thickness from a few feet to 20 or 30 feet. 

 The peat is largely dug for fuel, being cut in the summer season 

 and stacked. It holds a large amount of water, but the slowness 

 with which it parts with it is a great hindrance to its being largely 

 worked. When peat accumulates on a clayey surface abounding in 

 springs, the water sometimes oozes out beneath the peat, and 

 between it and the natural soil in such quantities as to raise up the 

 layer of peat so that it floats. Some areas of peat are known as 

 Quaking Mosses, and these owe their vibration to a semifluid 

 bottom, although some vibration is characteristic of all peaty 

 grounds. If swelled by heavy rains these Quaking IMosses 

 occasionally burst, as did the Sol way Moss in 1772, when a flow 

 of black peaty mud overwhelmed about 400 acres. ^ Peat is well 

 known to store up water on mountains. 



Lyell mentions that the formation of peat, when not completely 

 under water, is confined to moist situations, where the temperature 

 is low; and Prof. J. Geikie has pointed out that after the final 

 isolation of Britain from the Continent, the ancient forests decayed, 

 and peat-mosses largely increased on the higher grounds from 

 which they are now disappearing.'^ On mountains the peat is often 

 not more than 2 or 3 feet thick, and it is largely made up of Bog- 

 moss and Heather ; its growth depends in great measure on the 

 dampness of the air. 



Owing to the soft and yielding nature of some peaty deposits, 

 coins, bones, or other substances may often sink into or through 

 these 'sloughs,' and relics of various ages may thus be commingled. 

 Peat, as a rule, is a good preserver of animal substances, but in 

 some cases the humic and other acids met with cause their decay. 



Submerged Forests. — While Raised Beaches indicate an upward 

 movement in the land, there are many traces of old land-surfaces 

 along our coasts, submerged or partly so, which contain fragments 

 and stumps of trees, sometimes erect and with their roots embedded 

 in the old soil on which they grew. Trees and some other Plants 

 similar to those found in Peat, previously mentioned, occur in 

 these Submerged Forests. 



Such Submerged or Submarine Forests are not necessarily of 

 the same age, although those to which we now draw attention 

 are all probably Post-Glacial or Recent. On the other hand, the 

 Cromer Forest Bed, which in places is partially Submerged, is of 

 Pre-Glacial age, and earlier relics of terrestrial surfaces (not now 

 Submerged) are met with in the Purbeck Beds, and in the Coal 

 Measures. 



In many cases, as remarked by INIr. Godwin-Austen and Mr. 

 Whitaker, these Recent Submerged Forests are simply places where 

 the sea is eroding the peaty Alluvium of a river-valley, for they 

 frequently occur in prolongations of valleys which are now inlets of 



* Lyell, Principles of Geology, ed. xi. ii. 510 ; Gilpin, Pict. Beauty, etc., 1772} 

 T. R. Jones, P. Geol. Assoc, vi. 207. 

 ^ Trans, Roy. Soc. Edin. xxiv. 363. 



