106 GEOLoay of the isle ok wioht. 



most tropical of any that lias so far been studied in the northern 

 hemisphere. Following so immediately the flora of Sheppey, 

 with its wealth of Palm fruits, some denoting the largest species, 

 it presents us probably with an insiglit into the dicotyledonous 

 vegetation which accompanied them. Sifted a^ they have been 

 by the agency of water, only those leaves and bodies endowed with 

 certain powers of flotation were able to drift to that point ; the 

 heavy palm leaves and fern fronds, and the large leguminous pods 

 which give the Lower Bagshot flora its tropical aspect, have 

 been eliminated. These were left in higher reaches of the stream, 

 and we meet with them at Studland, where large quantities of Fern 

 and Palm are massed together, and at Creech Barrow near Corfe, 

 where the most magnificient opportunities for collecting fossil 

 plants have passed away, never perhaps to recur."^ 



The Reading flora has an exceedingly temperate facies, and 

 thus presents to us a relatively recent aspect. The Woolwich 

 flora is less temperate, for Palmettos appear in it. The Lower 

 Bagshot flora is like that of the London Clay, decidedly the most 

 tropical. The Middle Bagshot flora begins to lose its tropical 

 elements, and these appear to drop out very gradually and without 

 any sudden changes, down to the close of the Hamstead period, 

 when all traces of Eocene plants disappear from this country. 

 Allowance must be made for the fact that local accumulations 

 will of course present very different appearances and plant 

 remains derived from a sheltered and swam[)y station will appear 

 luxuriantly sub-tropical, which are not so, and conversely, leaves 

 blown from an arid spot may seem to indicate a harsher climate 

 than actually prevailed. 



The break betv/een the London Clay flora and those which 

 preceded it, is very great, and obviously due to a consider- 

 able increase of temperature. The connection between that of 

 Sheppey and of Alum Bay, though probably a good deal over- 

 estimated, is likewise due, it appears, to the high temperature 

 having been maintained, bringing in a vegetation that had not 

 been able to exist so far north since the close of the Cretaceous 

 period ; whence the Cretaceous aspect that has struck so many 

 observers. The break, which is very great indeed, between the 

 floras of Alum Bay and Bournemouth, deposited as they must 

 have been under very similar conditions, is far less easy to 

 explain. It is not one altogether of temperature, because there 

 are still many large palms in the latter, as L^iartcea, Fhceiiix, 

 Calamus, Nipa, with decidedly sub-tropical ferns. Some break 

 or change must have driven the then indigenous flora almost 

 completely away and brought in the new set of plants which 



* There are still fragments, some of them two feet in diameter, of enormous leaves 

 of fan palms, which might easily have been extracted entire, and parts of huge pods 

 of Cassia and Acacia, preserved in the Dorchester and Jermyn Street Museums and 

 in private collections ; but for upwards of 20 years no leaf deposits of Lower 

 Bagshot age have been found. The beds at Creech are much folded and leaf beds 

 of Middle Bagsiiot age are preserved in the folds, from one of which the large series 

 in the Oxford Museum must have been obtained, and from others I have more than 

 once myself been able t>) collect. — J. S. G. 



