Mild Polar Climates. 281 



flowing from a mountain-region supporting zones of vegetation of 

 all kinds from the tropical to the Arctic, if during the Eocene 

 period vegetation such as the present Arctic had come into existence, 

 of which we have as yet no evidence. Torrential floods may have 

 swept the remains of vegetation from the temperate zones of this 

 region into tributaries that conveyed it into the main river before 

 it was decayed or water-logged, where it became intermingled with 

 the remains of vegetation which grew in the tropical low ground 

 skirting the main stream, so that both sank together into the same 

 mud and silt"*. 



The elevated mountain regions from which he supposes 

 these temperate forms were derived he thinks might have been 

 Mull, 400 miles N.N.W., and Wales 200 miles N.W. Mr. 

 Gardner, however, showed most conclusively that Mr. Wood's 

 theory was based on imperfect acquaintance with the conditions 

 of the problem. The following is Mr. Gardner's reply : — 



" The leaves have never been drifted from afar ; they are often 

 still adhering to the twigs. The leaves are flat and perfect, rarely 

 even rolled and crumpled, as dry leaves may be, if falling on a 

 muddy surface ; still more rarely have they fallen edgeways and 

 been imbedded vertically. They are, moreover, not variously mixed, 

 as they should be if they had been carried for any distance, but are 

 found in local groups of species. For example, all the leaves of 

 Castanea have been found in one clay patch, with Iriartea and 

 Gleichenia ; none of these have been found elsewhere. A trilobed 

 leaf is peculiar to Studland ; the Alum Bay Aralia, the peculiar 

 form of Protectees, the great Ficus, and other leaves occur at Alum 

 Bay only. Each little patch at Bournemouth is characterized by 

 its own peculiar leaves. Such a distribution can only result from 

 the proximity of the trees from which the leaves have fallen. The 

 forms of most temperate aspect are best preserved, so that to be 

 logically applied, the Drift theory requires the palms, etc., to have 

 been drifted upwards. To suppose that most delicate leaves could 

 have been brought by torrents 400 miles from Mull or 200 miles 

 from Wales, and spread out horizontally in thousands, without 

 crease or crumple, on the coast of Hampshire, may be a feasible 

 theory to Mr. Searles Y. Wood, jun., but will not recommend 

 itself* to the majority of thinkers " f. 



Were there Glacial Epochs daring the Tertiary Age ? — Many 

 geologists, especially amongst those who are opposed to the 

 theory of recurring glacial epochs, answer this question em- 

 phatically in the negative. This belief as to the non-existence 

 of glacial conditions during the Tertiary period is, of course, 

 based wholly on negative evidence ; and this negative evidence 

 though strong is by no means perfectly conclusive, and 

 certainly not worthy of the weight which has been placed 



* Geological Magazine, 1877, p. 96. 



t Ibid. p. 138. 



Phil. Mag. S. 5. Vol. 18. No. 113. Oct. 1884. U 



