280 M. Utto Hahn on Eozoon canadense. 



in their arrangement. Where they are arranged somewhat in a 

 spiral line, this is to be ascribed to the circumstance that the 

 calcareous layer itself, from which they originated, had akeady 

 a circular or spiral arrangement produced by pressure, as 

 is shown in specimen III. This, however, is accidental. 

 Usually they are irregular in arrangement, position, and form. 

 I have observed such a canal under a power of 750 diameters. 

 No trace of calcareous envelope, or of tubular form ; the picture 

 is rather that of a fissure ; the canal is quite irregular, thicker 

 or thinner, and in a zigzag direction. 



In conclusion I have a remark to make with regard to the 

 limestone. This consists, like all primary limestones, of sepa- 

 rate individuals, distinctly separated from each other by their 

 lamination and a line, and in polarized light fully show them- 

 selves to be individuals by their different position. Many 

 individuals have the tioin cleavage-planes produced hy pres- 

 sure. I have here to refer to the discovery of Prof, von 

 Reusch, who produced the cleavage-planes by concussion. 

 This phenomenon of itself indicates poAverful pressure under- 

 gone by the mass after its solidification. Curiously enough 

 there are no canal-systems in the limestone individuals with 

 twin lamellfe. Moreover a canal-system generally does not 

 extend heyond one limestone individual. This is easily ex- 

 plained. The fluid could penetrate only into a still soft indi- 

 vidual ; it must therefore have found a limit at the next some- 

 what more hardened one. It must not be overlooked that the 

 canals, when they strike upon the serpentine mass or on 

 neighbouring individuals, become thicker, and terminate with 

 a kind of knob, the most certain evidence of a mass pushing 

 from behind and here coming to a stop. 



The canal-systems occur only where the serpentine mass is 

 elongated, transparent, and yellowish ; therefore only where 

 the whole mass was visibly completely metamorphosed, 

 softened, in fact, into a pasty fluid, and pressed while still in 

 this state ; for only thus could the original oli vine-forms be 

 converted into serpentine layers. Thus also are explained the 

 vertical lines in which the serpentine layers laterally strike 

 against a narrow limestone layer. 



Thus, then, there does not remain much to be said about 



3. The Zoological Facts. 



If we glance back over the previous results we have, for 

 every part of the Eozoon (the chambers, the walls with 

 columns, the film, the intermediate mass with large passages, 

 as well as the canal-systems), not only an adequate geologico- 

 mineralogical explanation, i)ut also the same phenomena in 

 rocks in which no one will speak of Eozoon-'s,{xMci\XYe^ unless, 



