438 Mr. J. Croll on the Change in the Obliquity of the Ecliptic, 



Let us now consider the effect that this condition of things 

 would have upon the level of the sea. It would evidently tend 

 to produce an elevation of the sea-level on the northern hemi- 

 sphere, in two ways. 1st. The addition to the sea occasioned by 

 the melting of the ice from off the antarctic land would tend to 

 raise the general level of the sea. 2ndly. The removal of the 

 ice would also tend to shift the earth's centre of gravity to the 

 north of its present position ; and as the sea must shift along 

 with the centre, a rise of the sea on the northern hemisphere 

 would necessarily take place, 



The question naturally suggests itself, Might not the last rise 

 of the sea, relative to the land, have resulted from this cause? 

 We know that during the period of the 25-feet beach, the time 

 when the estuarine mud which now forms the rich soil of the 

 Carses of the Forth and Tay was deposited, the sea, in relation 

 to the land, stood at least 20 or 30 feet higher than at present. 

 But immediately prior to this period we have the age of the 

 submarine forests and peat-beds, when the sea relative to 

 the land stood lower than it does at present. We know 

 also that these changes of level were not a mere local affair. 

 There seems every reason to believe that our Carse clay, as 

 Mr. Fisher states, is the equivalent of the marine mud with 

 Scrobicularice which covers the submarine forests of England*. 

 And, on the other hand, those submarine forests are not con- 

 fined to one locality. " They may be traced," says Mr. Jamie- 

 son, " round the whole of Britain and Ireland, from Orkney to 

 Cornwall, from Mayo to the shores of Fife, and even, it would 

 seem, along a great part of the western seaboard of Europe, as 

 if they bore witness to a period of wide- spread elevation, when 

 Ireland and Britain, with all its numerous islands, formed one 

 mass of dry land, united to the continent, and stretching out 

 into the Atlantic }, f. " These submarine forests/' remarks De la 

 Beche also, " are to be found under the same general condition 

 from the shores of Scandinavia to those of Spain and Por- 

 tugal, and around the British islands "J. Those buried forests 

 are not confined to Europe, but are found in the valley of the 

 Mississippi and in Nova Scotia and other parts of North 

 America. And, again, the strata which underlie those forests 

 and peat-beds bear witness to the fact of a previous elevation of 



* Quart. Journ. Geol. Soc. June 1866, p. 564. 



t Ibid. vol. xxi. p. 186. 



X Geological Observer, p. 446. See also Mr. James Geikie's valuable 

 Memoir " On the Buried Forests and Peat Mosses of Scotland," Trans, of 

 the Society of Edinburgh, vol. xxi v. ; and Chambers's e Ancient Sea- 

 Margins.' 



