On Variations of Sigillarice. 41 



From the analysis of Japanese copper, it would seem prob- 

 able that the iron and the traces of arsenic in the bronzes 

 are due to the crude copper used in making the alloy. The 

 lead was purposely added, probably to make the alloy more 

 fusible. Tin is found in Japan, but zinc and brass are ob- 

 tained from abroad. The presence of zinc, therefore, is a dis- 

 tinguishing characteristic of the modern bronzes. 



III. — On the Structure of Lepidodendron and Sigillaria . 



By HERMAN L. FAIECHILD. 



The science of Palaeontology has, up to the present time, 

 been in what may be termed its analytical stage. The general 

 tendency has been toward the separation of forms and the 

 creation of new species. This is doubtless in the natural 

 order of the development of the science ; but in vegetable 

 Palaeontology the establishment of new species has certainly 

 been carried to an extreme. It is admitted that Palseophy- 

 tology is greatly confused; and, indeed, from the fragmentary 

 character of fossil plants, much of this confusion is unavoid- 

 able. There is even yet a degree of uncertainty regarding the 

 true specific and even generic character of several groups. 

 But with all these causes of uncertainty, it is probable that 

 species and even genera have been somewhat needlessly mul- 

 tiplied, by regarding as sufficient for distinction,. variations 

 so extremely slight that in living plants they would scarcely 

 be noticed. 



Probably no genus is involved in greater confusion, as 

 regards the species, than either Sigillaria or Lepidodendron. 

 In these genera the chief, and in nearly every species, the only 

 feature upon which specific distinction can be based, is the 

 scar or cicatrice left by the falling leaf. If we judge by living 

 plants, and we are compelled to do so, these scars must vary 

 more or less with age, position on the plant, rapidity of growth, 

 leanness, the degree of decortication, and many accidental 

 circumstances. Only iu very rare instances, however, have 

 specimens of these gigantic palaeozoic plants been found suffi- 



