STATE OF THE GLOBE AT THE COAL EPOCH. 



603 



confirm the view that the trees were in situ. Ansted says, that although 

 many trees are found in the coal measures in an erect or highly in- 

 clined position, there is no reason for believing that they grew on the 



spot where they are met with. He rather thinks that they have been 

 caught or stopped in their passage down a rapid stream, and, like the 

 snags in some of the great American rivers, have been detained till 

 the lower portion was firmly embedded in the rapidly forming sand- 

 stone. The imbedding of stems hi strata of sandstone, is similar to 

 what Gardner saw near the mouth of the Rio San Francisco, where 

 coco-nut trees were found with their stems immersed to the depth of 

 50 feet or more in the embankment of sand which stretches along the 

 shore. Phillips remarks, that the condition of the plants which com- 

 pose the coal, the general absence of roots, the fragmentary state of 

 the stems and branches, the dispersed condition of the separable organs, 

 all confirm the conclusion that the plants have been swept down from 

 the land on which they grew by watery currents, often repeated, and 

 deposited in basins and large estuaries of the sea, or perhaps rarely in 

 lakes of fresh water. 



1187. Fossil Plants of the Secondary Strata. The plants of the 



Secondary series of strata are different from those of the Carboniferous 

 system. The Stigmarias, Sigillarias, and Lepidodendrons cease, and 



Fig. 810. Vertical stems of fossil trees, Calamites chiefly, found in the Coal measures of 

 Treuil, near Saint Etienne. 



