Mr. H. J. Carter on the Stromatoporidaj. 323 



on the other hand, is for the most part quadrangular and 

 separated by distinct vertical rods, that may be followed con- 

 tinuously through a plurality of layers. Moreover the ver- 

 tical section presents none of the transversely cut vessels 

 of the stelliform groups, which are almost always more or 

 less distinguishable in the vertical sections of Stromatopora. 

 If this be the " common species of Stromatopora " to which 

 Dr. Dawson alludes, then it is possible that he may be right. 

 At the same time it is evidently not a " common species 

 of Stromatopora^'' even if hereafter it should be found to be 

 any species of Stromatopora at all. The specimen is now in 

 tlie British Museum, and was kindly placed before me by Mr. 

 H. Woodward. 



After this, Dr. Dawson states that the " corallum oi Milleporay 

 on the contrary, has no concentric laminas." How does this 

 accord with the following desci-iption by Mr. Moseley of the 

 living species he found at Tahiti, viz. " Layers more or less 

 continuous occur in the more massive coralla, appearing in ver- 

 tical sections as lines of calcareous matter running parallel to 

 the surface of the corallum, and indicating successive stages of 

 growth " {op. et I. c. p. 121) ? Besides, the weathered end 

 of any old piece of Millepora alcicornis^ if cylindrical, will 

 show this. Indeed it is difficult to conceive how it could be 

 otherwise. 



The allusion to my not being aware that " the stelliform or 

 radiating canals do not occur in the common species of Stro- 

 matopora''' has been answered; and the hint that my expe- 

 rience in these matters is " limited " is not worthy of a reply. 



But when Dr. Dawson adds that it is " difficult to under- 

 stand" the meaning of my observations on the so-called Eozoon 

 in the paper under reference (Ann. 1878, vol. i. p. 310), I 

 would here observe, by way of explanation, that when the 

 structure of the crystalline stratified rocks called " Eozoon ca- 

 nadcnse''^ resembles organic remains as much as the play of 

 glauconite in the trap-agates of Western India or any other 

 part, it will be quite time enough to consider whether it is of 

 organic or mineral origin. At present, all that I can state of 

 it, after having examined many typical specimens, besides 

 some in the rough state lately sent to the British Museum 

 from Canada, is that it consists of a laminated structure, and 

 that when it shall be found to present the other stnictural 

 features of Stromatopora (to which Eozoon is now said to be 

 allied) in addition to this lamination, which is as common 

 in mineral as in organic structure, then, and then only, will I 

 admit its organic origin. 



Lastly, when Dr. Dawson offers " mail chippings " for mi- 

 croscopical examination, as if his own opinions had been settled 



22* 



