M. Otto Halm on Eozoon canadense. 273 



from the sides, cylinders with an elliptical section would be 

 formed, and by further pressure finally strata (layers) in the 

 limestone mass. But if, as in specimen III., unequal pres- 

 sure occurred, the layers must have been broken up and torn 

 to pieces ; but the parts would then, where they liardened, show 

 granular structure in their section. It cannot be asserted that 

 the intervening calcareous mass was hardened or even present 

 before the serpentine ; otherwise the fluidal structure would 

 no longer be explicable. 



The canal-systems are of very different diameter ; they 

 also differ with regard to their distribution and form. They 

 consist of carbonate of lime. Nowhere do we see around 

 them an envelope like shell-substance, but they rather vanish 

 into the surrounding material. 



I also investigated : — 



IV. Serpentine limestone from the Bayerische Wald. The 

 sequence is limestone, limestone with graphite, limestone with 

 serpentine, granular as in III., serpentine, limestone with ser-; 

 pentine, limestone with graphite. Distinct chrysotile layers 

 round the serpentine grains. No trace of canal-systems. 



V. Serpentine limestone from Krummau (Bohemia), from 

 Professor von Hochstetter. 1. A similar specimen treated with 

 acid. 



The limestone is coloured grey by black enclosures. A 

 large, much divided serpentine layer. The serpentine is 

 enveloped by a layer of chrysotile, which appears as a fine 

 white line. No canal-systems. 



VI. Another serpentine limestone will be mentioned below. 

 All the serpentine limestones at command, especially from 



Elba and Lissiz, were examined. Much as the latter re- 

 sembles II., no trace of the canal-systems could be found, 

 but there were chrysotile shells. With regard to the latter, 

 I refer the reader to Draschkc, in Tschermak's ' Mineralo- 

 gische Mittheilungen,' 1871, Heft i. p. 1. 



Further, about thirty serpentines, from the pseudomorphic 

 crystals of the Snarum to the pure sedimentary rock, and, 

 lastly, all the primary limestones at my disposal were ex- 

 amined, and, finally, about twenty gneisses. In that of Mont 

 Blanc I recognized the canal-systems. 



IV. 



I regarded it as the simplest course, with respect to the 

 description of the Eozoon-xook, to allow its first investigator, 

 if not its discoverer, to speak. Little has been added to his 

 description of Eozoon canadense. Giimbel thought he detected 



