ANNIVERSARY ADDRESS OF THE PRESIDENT. xU 



duced alternations of deposits, which should at one time contain the 

 remains of marine animals Avhich inhabited the coast seas, and were 

 quietly entombed, and at another the remains of plants, showing their 

 growth on the spot. Such evidence we seem to possess at two distinct 

 periods in the north of England, where we detect alternations of coal 

 beds, with their underclays, and limestones with marine animal re- 

 mains of the carboniferous time ; and also find a coal accumulation, 

 with some plants apparently in the position in which they grew, of 

 the oolitic series. In both cases the evidence would be in favour of 

 quiet depressions, low districts with land plants growing upon them 

 so sinking beneath sea-water, that marine creatures swarmed over the 

 previous dry land, their remains entombed amid detrital deposits 

 effected at the time. 



Viewing the actual and varied altitudes above the sea-level of lakes 

 in different parts of the world, the plants which may be drifted into 

 them and preserved amid any mud, sand, or calcareous matter depo- 

 sited in such lakes, give us no just idea of the climate of the time at 

 the sea-level in the same latitudes. For instance, the plants drifted 

 into the lakes of Switzerland and Northern Italy, some of which may 

 even be swept from heights approaching lines of perpetual snow, 

 would not give us the climate of the coast of the Bay of Biscay be- 

 tween the Saone and the Gironde, though in the same general latitude. 

 Then, again, as to the conditions for the transport of plants or their 

 parts to situations where portions of them may be more or less pre- 

 served in detrital matter, much has to be considered. Though floods 

 in high regions tear up trees and smaller plants in their course, the 

 chances of any of the plants reaching sea-coasts depend upon a va- 

 riety of conditions, among which proximity to the sea is one of no 

 inconsiderable importance. Thus w^e have seen the arborescent ferns 

 and other plants of the higher lands of Jamaica swept by floods into 

 the adjoining seas (becoming entangled in part among the mangrove 

 swamps at the mouths of the rivers), the distance ha\ing been so 

 short, that many stems of the fern trees, their fronds, and those 

 of other ferns of the higher regions, were not much injured. No 

 mere swelling of the rivers from rains on the lower grounds, which did 

 not cause torrents to wash away plants in the higher lands, would 

 bring down a frond of these ferns ; it would, however, sweep on many a 

 lowland plant, and not a few of those Avhich grew in the river courses 

 during the dry weather, into the mangrove swamps and the sea. 



In great rivers, the leaves, as they fall from trees overhanging the 

 w'ater, are floated onwards and often carried quietly to sea, sometimes 

 from long distances inland. Plants and their parts may, under fa- 

 vourable conditions, be washed into, and be preserved in the mud of 

 climates where they do not grow. They may be thus brought by the 

 Mississippi, the Paraguay, the Nile, and the great rivers of Northern 

 Asia flowing from south to north, and be preserved under climates 

 differing from those where they flourished. AVe have no reason to 

 suppose that the conditions of continents, as regards the flow of rivers 

 into the sea, were not very various during long lapses of geological 

 time, and we should very carefully avoid permitting our view of the 



