244 THE PLANT WORLD 



doubt this, and the matter must remain in question. One thing is cer- 

 tain, if mosses were present in the Carboniferous age they were not 

 abundant, and could hardly have played a very important part. 



The arguments for the presence of mosses during Mesozoic time 

 are hardly stronger than for their Palaeozoic origin. Many years ago 

 Professor Heer, a celebrated student of fossil plants, predicated the 

 presence of mosses in the Jurassic (Liassic) from the occurrence of 

 fossil caterpillars in these beds, these insects being of a type known to 

 feed on mosses, but this can hardly be accepted as scientifically sound. 

 So far as now known not a single species of fossil moss has been found 

 in rocks of Mesozoic age in North America. 



But when we come to the Tertiary age the matter, as might be ex- 

 pected, assumes a more hopeful phase. The earliest extinct species re- 

 corded for America was described by Mrs. E. G. Britton, in 1899, from the 

 upper Eocene at Cle Elum, Washington, under the name of RhyncJio- 

 stegmm Knowltoni. It is a small sterile stem about 1 cm. in length and 

 bears rather scattered two-ranked leaves. Mrs. Britton regards it as 

 being related to the living R. rusciforme. The only other supposed 

 extinct American species was described by Lesquereux as Hi/pnum 

 Haydeni, from the Eocene of Colorado, but it seems more than likely 

 that this should be referred to Lycopodium. In addition to these, 

 fragments of several living species have been found in the Pleistocene 

 deposits of Canada, and this completes the list of our fossil mosses. 



In other parts of the world conditions during Tertiary times were 

 more favorable for preserving mosses, and some thirty more or less sat- 

 isfactory species have been described. The Baltic amber, which is so 

 widely celebrated for its inclusions of often beautifully preserved in- 

 sects and various plant fragments, has supplied several species of mosses. 

 These represent living genera, and other European deposits of recent 

 geological age have afforded a number that have been referred, either 

 definitely or provisionally, to living species. So far as I know the only 

 fossil moss that has been found with the capsules preserved is from the 

 Tertiary deposits of Montabauer. This was called Gh/mnostomum ferru- 

 gineum but has since been referred to Sphagnum, and is supposed to be 

 related to the living S. cymhifolinm. 



From this hasty review it appears beyond question that our knowl- 

 edge of fossil mosses is extremely limited, and since the study of fossil 

 plants has been so widely prosecuted in different parts of the world 

 without disclosing man 3^ of their remains, it is hardly to be expected 

 that our information will ever be very extensive. Yet it should not be 

 forgotten that this is only negative evidence, and perhaps " to-morrow " 

 some fortunate collector may happen upon a deposit that will show an 

 abundance of these plants. 



