HARDWICKE'S SCIENCE-GOSSIP. 



97 



THE FLORA OF THE PAST. 



No. II. 

 By Mrs. BODINGTON. 



,HE Huronian age, 

 succeeding the Lau- 

 remian, seems to 

 have been a dis- 

 turbed and unquiet 

 time, and gives no 

 evidence of vegeta- 

 tion except in cer- 

 tain dark slates 

 coloured with car- 

 bonaceous matter. 

 In the Cambrian, a 

 great subsidence of 

 our continents be- 

 gan, which went on 

 with local intermis- 

 sions all through 

 Siluro-Cambrian 

 times. Certain im- 

 pressions on old 

 Cambrian rocks in Sweden, present very plant-like 

 forms, and received from the Swedish geologist 

 Linnarrson the name of Eophyton, or Dawn-plant. 

 They are wanting, however, in any trace of carbon- 

 aceous matter, and Sir J.-, W. Dawson thinks they 

 seem to be rather the grooves or marks cut in clay by 

 the limbs or tails of some aquatic animal, and after- 

 wards filled up and preserved by succeeding deposits. 

 The same remarks apply to many supposed traces of 

 plants, which, under close examination, appear to be 

 only the burrows or trails of worms and crustaceans. 

 A frond of sea-weed is closely imitated by the trail of 

 the modern king-crab. The oldest plant, of whose 

 genuine vegetable nature Principal Dawson has no 

 doubt, was presented to him by Dr. AUeyne Nichol- 

 son, of Aberdeen, and has been named Protannularia. 

 It was found in the Skiddaw rocks of Cumberland, 

 and shows traces of a graceful reed-like form with 

 whorls of terminal leaves. It is allied to the 

 modern Rhizopods, of which an account will be 

 given further on. Only two other traces of genuine 

 No. 293. — May 1889. 



plants have been found in the Siluro-Cambrian. In 

 the Upper Silurian strata, the evidences of land 

 vegetation somewhat increase. Amongst these early 

 plants is one of extraordinary interest, for it seems to 

 be a survival of those Tree Sea- Weeds, whose 

 remains may have contributed to form the Archaean 

 beds of graphite. It appears to be one of the un- 

 varying laws of evolution that the lower organisms 

 tend, in the absence of competition with higher forms, 

 to attain immense proportions. Such, for instance, 

 were the Eurypterids, the giant crustaceans of Upper 

 Silurian times, when fish were few and small ; the 

 huge newts of the coal forests, before the advent of 

 reptiles ; and the terrific reptiles of the Lias, which 

 far exceeded in size any land animals that have 

 existed since. So, too, we have the giant club- 

 mosses and horse-tails of the coal-forests, before the 

 appearance of the higher plants. We might there- 

 fore easily have imagined a sea-weed tree, before the 

 days even of club-mosses and horse-tails, but it is in- 

 finitely more interesting to have the fossil remains of 

 such a plant. 



Sir J. W. Dawson has named this strange fossil 

 Nematophyton. In 1870, he was shown some spore- 

 cases or seeds from the Upper Ludlow beds (Silurian) 

 of England, which Sir Joseph Hooker had described 

 as Pachytheca. In the same slabs v/ere found 

 fragments of fossil wood, identical with a fossil tree 

 from the Devonian or Lower Erian of Gaspe, New 

 Brunswick, described by Sir J. W. Dawson as early 

 as 1859. The wood of this singular tree shows a 

 tissue of long cylindrical tubes, like slender hair-like 

 worms in vertical section, and traversed by a com- 

 plex network of thinner-walled and smaller-sized 

 tubes. The trees were of large size, with a coaly 

 bark, and large spreading roots ; the stem being 

 smooth or irregularly ribbed, and having a jointed 

 appearance. Professor Penhallow, of McGill 

 University, was asked to examine Nematophyton, 

 and part of his report is as follows : — ' ' The structure of 

 Nematophyton as a whole, is unique ; there is no plant 



