RESULTS OF PAL^ONTOLOGICAL RESEARCH 53 



at least a contemporaneous origin for both, yet the 

 occurrence of graphite does not suffice to afford a 

 proof of this, ' because/ as Kayser says, 1 ' in no case 

 should the accidental chalk and graphite deposits of 

 the gneiss be regarded as proofs of organic life in the 

 Primary period, since chalk and graphite, as it can be 

 proved, may arise also on inorganic lines/ 



The first certain traces of growth in recognizable 

 remains we find in the Silurian formation. The alleged 

 seaweeds of the pre- Cambrian and Cambrian systems 

 must to a large extent be otherwise explained. 



After the experiments reported by Nathorsh it is 

 impossible longer to refrain from the opinion that c a 

 large number of the smaller fossil algae are either the 

 results of processes in rock formation or animal tracks, 

 or furthermore are produced by running water or plants 

 moved by water/ or, as is stated farther on, ' the remains 

 of tissues of more highly organized plants/ 2 



The Silurian remains, fern fronds, and large masses 

 of algae (bladder algae Siphonae), show us that there were 

 already representatives of the higher systematic groups. 

 By reason of the simple arrangement of the veinlets 3 in 

 the fronds the first ferns are designated as 'primitive/ 4 



1 Farmationskunde, p. 21. The evidence was mainly provided by 

 Weinschenk. 



2 A. Schenk, in Zittel's Handbuch V, p. 233. By this the existence 

 of vascular plants was indicated. More details cannot, however, be 

 recognized owing to the great decomposition of the materials. 



3 The veinlets are bundles of conducting vessels by which water and 

 earthy salts in solution are carried to the assimilating tissues. 



4 More details are given in 3, where we shall treat of the differentia- 

 tion of the fern type. 



