128 Fussil Land Plants, as illustrative of 



permitting our vivv uf the relative disposition of land and water at- 

 former periods to bo biased too far by their present ai-rangement. 



Every autumn our European rivers are full of leaves which have 

 quietly fallen into them. Some get washed on the banks, while 

 others are left upon low grounds whin the waters may have been 

 more swollen at one time than another. Some get borne backwards 

 and forwards by the tides in estuaries, and are accumulated in the 

 mud, entangled with the remains of estuary animals and plants ; 

 but many get washed to sea, particularly if off-shore winds prevail 

 at the time. Probably many of these become satuiated with sea- 

 water and fall to the bottom amid the remains of marine molluscs 

 and other animals, and are thus entombed with them amid any de- 

 tritus there accumulating. Some we know are thrown on shore, at 

 various distances from the i-iver-mouths, according to the prevalence 

 of the winds at the time, and the relative bearing of these upon the 

 coasts of the locality, and become intermingled with various marine 

 animal and vegetable remains. 



The extent to which trees and smaller plants are washed during 

 floods out of the great rivers of the world, and floated outwards to 

 situations where they fall within the influence of ocean currents 

 and prevalent winds, is very considerable ; and it is very needful to 

 bear this in mind when we have no satisfactory evidence as to the 

 arowth of plants at or near the localities where we find their fossil 

 remains. Little islets of matted plants are thus sometimes floated 

 away, and it will depend upon the weather they may encounter how 

 long they may keep together before they become broken up by the 

 seas, and fall to the bottom. Although the counter-current along 

 the Atlantic shore of the United States may tend to carry plants 

 washed out from the rivers of that part of North America to the 

 southward, the Gulf Stream is still enabled to transport plants and 

 their parts from Cuba and the Bahamas (the prevalent trade-winds 

 even perhaps drifting them from Hayti) northerly towards New- 

 foundland. Taking the Gulf Stream and its counter-current along 

 the American shore as constants, we may have two north and south 

 belts beneath, in one of which the remains of plants from the north 

 are accumulated, and in the other those from the south, indicating 

 climates which do not correspond with those of the dry land of 

 America in the same latitudes. Such lines of transport — and there 

 would appear to be many of them — and the probable falling of 

 plants and their parts, to the bottom during a long period of time, 

 have to be regarded when we consider deposits wherein the remains 

 of plants which may not have grown on the spot are entombed. 

 There may be situations where little detrital matter now settles, 

 but where drifted vegetable matter may accumulate from the repe- 

 tition of certain annual effects continued through long time, as well 

 as those deposits which we infer have been the result of the 

 growth of plants on or near the spot where their remains are now 



