40 PKELIMINARY INQUIRIES. 



possible, is inconsistent witli the close similarity of tlie floras of these lands, with the configura- 

 tion of the bed of the neighbouring sea, and with other facts having a like bearing. 



The European character of the plants and insects of Greenland, Iceland, and Spitzbergen, is 

 sufficient evidence that they must have been connected with Europe in some way, but that alone 

 throws but little light on the point of connexion. It may have been by Norway, by Nova Zembla, 

 or by Britain. The following considerations show that it must have been by the latter : — 



No tree now grows in Orkney or Shetland; the only ligneous things that do grow are the 

 Betula alba and the common juniper, both merely existing as shrubs ; but at six feet beneath 

 a peat-bog, trees, branches, leaves, and cones, ascribed to the silver fir, have been fovind — one tree 

 in particular of six feet in circumference and forty feet in height,* being recorded by Mr. Edmon- 

 ston as having been found in peat in Shetland. 



Wlien did these trees grow, and what was the climate of Britain then ? Was it really milder 

 then than now, as we should be inclined to expect, from the fact of these trees being found in 

 Shetland, where they will not now grow ? As to the date of their growth there, there can be very 

 little doubt that it was subsequent to the glacial epoch. The grinding of the ice of that time would 

 sweep away every trace of peat-bogs from the surface of the land. Were a Swiss glacier to meet a 

 peat-bog in its course, it would soon plough it up, and scarify the ground to the very bone below. 

 It is plain, therefore, that the tree must have grown and died, and the peat been deposited, subse- 

 quent to the glacial epoch. 



Now one of two things must have taken place since it grew ; either the general climate of the 

 Northern hcmisjjhere must have undergone a change, and that change must have been from warmer 

 to colder, or the individual climate of Shetland must have done so by an alteration in its configura- 

 tion and physical condition. 



But the growth of these silver firs (if silver firs they be and not spruces, a point on which the 

 record is not absolutely clear) could not be due to any material change in the general climate 

 of the whole country : for their remains are found in the peat, in company with those of the Scotch 

 pine and spruce fir, and as these are the same trees that now grow in the corresponding isothermal 

 line on the Continent, no general alteration from warmer to colder can well have taken jolace over 

 the whole hemisphere ; and as it is only on the Continent or in lands not exposed to the sea that 

 they thrive in that latitude, it may be inferred that at the time they grew there the Shetlands 

 were either not islands, or not such small islands. 



But the Shetland Islands rise nearly precipitously from a wide submarine plain seventj'-four 

 fathoms deej), which extends from these islands to within no great distance of the coast of Norway. 

 Their form, therefore, shows that any increase on their size could only be obtained by such an eleva- 

 tion as would unite them to the Continent, from Denmark southwards ; and there is little doubt 

 that that must have been the position of matters when the trees in question grew on these islands. 

 Along the west coast of Norway a deep channel extends in continuation of that of the Baltic. 

 That sea then must have trended away up by the west coast of Norway, and Britain must have 

 been joined on to the present Continent from the Shetlands to the north of Denmark, all south 

 of a line drawn between them being, much less than seventy-four fathoms in depth. The Rhine 

 and the Elbe, so soon as by the subsequent rise of the land they came into existence, probably 

 emptied themselves into the Baltic. 



* Edmonston, in " Annals of Natural History," 1841, vii. 295, and Edmonsion in " Pliytologist," i. 430. 



