34 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



Alex. Brongniart^° announced that peats, consisting wholly of leaves, 

 had been observed in Holland and that similar deposits, formed of 

 leaves from resinous trees, occur in the Jura. There are very many 

 peat deposits without Sphagnum. It and other mosses occur rarely 

 in the peats of Florida and it seems to be wanting in the Kampar- 

 Siak area of Java. Molengraaff asserts that mosses contribute 

 little to the peats of central Borneo. C. A. Davis has shown that 

 Sphagmiui is a comparatively late comer into the Michigan peats 

 and that it is still absent at a great proportion of the localities. 

 Even in northern Europe, many observers have made it clear that 

 mosses are only a few of the peat- forming plants ; and in the older 

 deposits there are thick benches in which Sphagnum is almost or 

 altogether wanting. But mosses are all-important in arctic and 

 sub-arctic deposits of this day, while they are comparatively unim- 

 portant in those of the temperate and sub-tropical as well as 

 tropical areas. 



Sedges appear to have been the most important peat producers 

 in much of the north temperate zone; but a peat deposit is not the 

 product of any single plant or group of plants, though this is not 

 to deny the existence of such deposits, for they do occur under 

 exceptional conditions. In the southern part of the United States, 

 one finds conifers and deciduous trees making the chief contribu- 

 tions ; the condition is evidently the same in central Borneo, where 

 according to Molengraaff, the peat consists almost wholly of re- 

 mains of trees, and Koorders makes a similar remark respecting 

 Java. Any plant, apparently, may become a peat-maker ; the 

 hyacinth, introduced into Florida, where it threatened to ruin the 

 navigable rivers, has become a peat-producer of no little importance. 

 Certain members of the palm family contribute to the peat deposits 

 of Florida and it appears altogether probable that, when the peats 

 of the Amazon, Orinoco and Paraguay have been studied, palms 

 will be found among the most important of the contributing plants. 



It is well known that the sedge-association, in advancing from 

 the shore of a lake or pond, is very apt to form a floating mat. One 



20 Alex. Brongniart, " Traite elementaire de mineralogie," Paris, 1807, 

 T. II., p. 41. 



