282 PLANT LIFE. 



been in course of time transformed into " cannel " 

 coal. In what is now the Welsh coal basin, heat 

 or pressure, or both, fused the carbonaceous matter 

 and turned it into the hard, shiny, formless condition 

 now called anthracite, which is the best steam coal for 

 naval purposes. Ferns and their allies are therefore 

 of great historical interest, although their importance 

 to-day is by no means great. 



Unfortunately, authorities on fossil botany differ very 

 widely in their views as to the nature of many plant 

 remains, and it is not possible to give a definite and 

 clear account of the first appearances of any of the 

 groups that are now in possession of the earth. 



It is probable that the first living creature was 

 of the nature of an Alga, because, to assimilate 

 carbonic acid or form sugar, seems to require the aid 

 of chlorophyll ; and with regard to those few animals 

 which possess green chlorophyll in their bodies, the 

 green matter seems to be really an alga contained 

 within the animal. The modern algae are confined 

 either to water, or to the thin film of moisture which 

 covers very wet rocks or soil, and they are unable 

 to exist on dry land. The most probable guess as 

 to the nature of the first dry land plant is that it 

 was a Lichen consisting of an alga and a fungus 

 living together. 



Unfortunately, there is much uncertainty as to fossil 

 Algae, Fungi, or Lichens, owing, no doubt, to their soft, 

 fleshy character, which would always make their 

 preservation a mere accident, not likely to occur at 

 all frequently. Many fossils which have been named 

 and described as seaweeds, turn out to be only markings 

 of the soil due to all sorts of causes. For example, 

 the casts of animal tracks, such as those of certain 



