xlii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



relative disposition of land and water at former periods to be biased 

 too far by their present arrangement. 



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 when the waters may have been 

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

 and foi-^'ards 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 saturated 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 detritus there 

 accumulating. Some we know are thro\\ai on shore, at various di- 

 stances from the river-mouths, according to the prevalence of the 

 winds of 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 growth 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 Haiti) northerly towards Newfoundland. 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 cor- 

 respond 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 repetition of certain annual efl'ects continued through long 

 time, as Avell as those deposits which v/e infer have been the result 

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

 now found. When we consider all the conditions under whi^^h the 

 remains of plants may be accumulated, and the difficulty often of de- 

 termining the real character of the plants themselves *, it would ap- 



* See Dr. Hooker's Remarks, Memoirs of the Geological Society, vol. ii. 



