294 On a Suhmanne Forejl 



which dedroycd it, lowered the level of the ground where it 



liood. 



There is a force of fubfidence (particularly in foft ground), 

 which, being a natural confequence ofgravity flowly though 

 perpetually operating, has its aftion fometimes quickened 

 and rcndi red fudden by exirancous caufes, for inftance by 

 earthquakes. The How eftefls of this force of fubfidence 

 have been accurately remarked in many places : cxaijiplcs 

 alfo of its fudden adlion are recorded in almod every hittory 

 of great earthquakes. Tlie fhorcs of Alexandria, according 

 to Doloniicu's obfervations, are a foot lower than they were 

 jn the time of th.e Ptolemies. Donati, in his Natural Hift, 

 tory of the Adriatic, has remarked, feemingly with great ac- 

 curacy, the efie&s of this fubfidence at Venice ; at Pola in 

 Iflria; at Lifs, Bua, Zara, and Diclo, on the coafl of Dal- 

 matia. In England, Borlafe has given, in the Philofophical 

 Tranfaftions*, a curious obfervation of a fubfidence, of at 

 lead fixteen feet, in the ground between Sampfon and Tref- 

 caw iflands in Scilly. The foft and low grounds between 

 the towns of Thorne and Gowle iri YorkOiire, a fpace of 

 nianv miles, has fo much fubfided in latter times, that fome 

 old men of Thorne afiirmcd, "that whereas they could be- 

 fore fee little of the ftecples (of Gowle), they now fee the 

 church-yard wall f-" The inftances of fimilar fubfidence, 

 which might be mentioned, are innumerable. 



The force of fubfidence, fuddenly afting by means of 

 fome earthquake, feems to me the moft probable caufe to 

 which the ufual fubmarine fituation of the foreft we are fpeak- 

 ing of may be afcribed- It affords a fimple, eafy explana- 

 tion of the matter; its probability is fupported by numberlefs 

 inftances of fimilar events ; and it is not liable to the ftrong 

 obje6lions which exifl: againft the hypothefis of the alternate 

 dcpreflion and elevation of the level of the ocean; an opinion I 

 v/hich, to be credible, requires the fupport of a great num- 1 



Vol. XLVIII. p. 62. t Cough's Camden. 



bcrl 



