503 



THE GEOLOGIST. 



reaching from the Nen to the Witham, with a view to the protection of the 

 low lands from the injuries they were subject to from the fresh water flowing from 

 higher levels towards the Wash. But besides the former forests of the fen-lands 

 within the boundary of the Roman sea- bank, large tracts of similar lands, covered 

 also with the roots and trunks of trees, are not unfrcquently revealed at very low- 

 tides along the Lincolnshire coast u-ithout its ancient maiine barrier. The 

 question that arises most naturally as to how these became submerged, will now 

 demand our consideration. 



This fact has always been looked upon as a great mystery by the few scientific 

 men who have turned their attention towards it, and various theories have been 

 advanced for the purpose of solving the dilBcuity it presents to us. Some have 

 thought that it has been caused by a change in the coastal line, some by the 

 agency of earthquakes, and others by the subsidence of the land ; whilst the 

 fen-lands of the interior have generally been considered to have been formed 

 through the neglect of the Saxons, in paying no attention to the system of 

 artificial drainage introduced by the Romans, which occasioned floods to arise of a 

 permanent character, the results of which are still so plainly evident. This last 

 theory, however, is utterly untenable, as portions, at least, of the Roman sea-bank 

 have been raised upon that very peaty stratum filled with roots of trees, which 

 we are anxious to account for, and therefore it must have been formed before the 

 Roman occupation of this part of Lincolnshire, Finding that the submersion of 

 these forest-lands was not caused by the interference of art with nature, and that 

 they extend beyond the sea-bank, and far below the usual level of the sea, the 

 next theory that has been brought forward is, that they owe their origin to a 

 change in the coastal line through the action of the sea. 



Doubtless great changes have taken place in the form of the Lincolnshire coast, 

 and many large estuaries are now completely filled up v.-hich are known to have 

 formerly existed there, whilst from the remains of f-rest-produce beyond its 

 present sea coast, it is clear that the land once extended far more to the east 

 than it does now, but we can scarcely suppose, as has been suggested, that a 

 higher ridge of land once existed beyond the present tidal line, serving to protect 

 a plain lying below the sea level, of which the tree-covered islets, still occasionally 

 visible, are a portion. The next theory, however, with regard to the phenomenon 

 we are treating of, I believe to be the true one. and that is, that the large por- 

 tions of the lowlands of Lincolnshire have sunk below their original level. 

 Sub -marine forests are by no means uncommon ; in Yorkshire several instances 

 may be brought forward, such as that at Outhorne and other points on the 

 Holderness coast. In Hartlepool Bay the remains of a similar forest occasionally 

 excites much attention when revealed during the lowest neap tides, amongst which 

 are found horns and bones of the ox and red deer, and even the wing-cases of 

 land-beetles. The south coast possesses many examples of the same character, 

 such as the tract between St. Michael's Mount and Xewlyn, the former of which, 

 according to Carew, was termed in old days " the rock in the icood," and another in- 

 stance was lately revealed by the shifting of the sand in Padstow harbour, whilst a 

 similar phenomenon attracted the attention of Giraldus deParri, or Cambrensis, as 

 long ago as 1 188 on the shores of South Wales. Most of the examples of these sub- 

 marine forests, if not all, that have come under my notice can only be accounted 

 for, in my opinion, by the subsidence of the land. This theory may appear more 

 marvellous, and therefore less likely to be true than the preceding ones, but 

 when we find from the study of geology that certain strata, the undoubted deposit 

 of water, are now upheaved far above the reach of that element, and that large 

 tracts of land have sunk beneath it, we can only regard such changes as one of 

 the usual, but always wonderful operations of nature. Strabo was well acquainted 

 with this motive power in the earth's crust, as well as are our leading modern 

 geologists, but as it may be supposed by some that such motive powers are now 

 no longer exercised, it will be well to mention an instance of the subsidence and 

 elevation of land during the historic period. I will allude, therefore, to that noted 

 example aftbrded by the district about Pozznoli, in the Bay of Bai£e, and especially 

 made manifest by the pillars of the Temple of Jupiter Serapis at thut spot, and 



