the Earth at different Epochs, S^c. 368 



considerations, have equally been led to admit that, at the epoch 

 when the coal formations were deposited, the continents must 

 have had less extent, and the seas must have covered a greater 

 surface than now. The considerations of primeval botanical 

 geography which we have above detailed, seem to us to give 

 much more probability to this supposition. 



Geology and botany, therefore, appear to us to agree in an- 

 nouncing that, at this epoch, the parts of the earth which rose 

 above the waters formed only islands of small extent, disposed 

 in archipelagoes in the midst of vast seas. 



It was on these islands that the plants grew whose remains 

 have given rise to the coal beds, and of which we still find some 

 untouched remains in the rocks which accompany these beds of 

 combustible matter. As to the manner in which these beds them- 

 selves were formed, it belongs, for many reasons, more to geo. 

 logy than to the botany of the ancient world. I cannot, how- 

 ever, avoid saying a few words with respect to it, for, in some 

 respects, this phenomenon is probably connected with the man- 

 ner in which these vegetables grew at the surface of the soil. 



Geologists have formed very different ideas respecting the 

 origin of this combustible ; and, to speak only of those who at- 

 tribute it to the vegetables which then grew upon the earth, 

 the only opinion which appears to us to be now admissible, 

 some have considered the beds of coal as a kind of peat depo- 

 sites of greater or less extent, formed by the remains of vegeta- 

 bles, and on which other vegetables still grew, while others have 

 regarded these beds as formed by a sediment of decomposed 

 vegetable matters, at first held in suspension in the water of the 

 sea, and afterwards deposited at the bottom of that fluid. 



The former of these hypotheses, which has for its author the 

 celebrated Deluc, appears to me to accord better with the gene- 

 ral disposition of the coal deposites, and several of the remarkable 

 circumstances which they present, such as the pretty frequent 

 existence of trunks of trees still placed perpendicularly to the 

 strata in the direction which they must have occupied during 

 life. The other hypothesis, which has in these latter times been 

 supported by MM. Sternberg, Boue, and Constant Prevost, 

 perhaps, more easily explains the alternations of beds of coal 



