No. 2.] DAWSON — EOZOON CANADENSE. 107 



questions in hand. The following considerations will serve to 

 indicate the weak points of the memoir. 



1. A number of errors and omissions arise from want of study 

 of the fossil in situ, and from want of acquaint-?.nce with its 

 various states of preservation. Trivial errors of this kind are 

 his referring to my photograph in Plate III, of the " Dawn of 

 Life," as if it were natural size, and his stating that the larger 

 specimens have fifty laminae, whereas they often have more than 

 an hundred. More important is his failing to appreciate aright 

 the occurrence of Eozoon in certain layers of regularly bedded 

 limestones, the rounded or club-shaped forms of the more perfect 

 specimens, the manner in which the layers become confluent at 

 the edges of the forms, as described by Sir W. E. Logan and 

 myself, or the amount of crushing and fracture which most of 

 the specimens exhibit. Thus he fails to convey any adequate 

 idea of the Strom atoporoid forms and mode of occurrence of the 

 organism, or indeed of its general character and probable mode 

 of growth. Farther he treats it from the first as a mere lamin- 

 ated aggregate of calcite and serpentine, without reference to its 

 occurrence in any other state, and also without reference to the 

 fragmental limestones in part made up of its remains. He ob- 

 jects strongly to the want of definiteness of form and distribution 

 in the chambers and connecting passages, w^ithout making 

 allowance for defects of preservation, or mentioning the similar 

 want of defined form in some Stromatoporce. He admits, how- 

 ever, that the modern Carpenttria and its allies are in some 

 respects equally indefinite. He farther objects to the impos- 

 sibility of detecting regular primary chambers like those in 

 modern foraminifera, but seems not to be aware that, as I have 

 recently shown, some Stromatoporce originate in a vesicular, 

 irregular mass of cells, and that in Loftusia, both the Eocene 

 L. Persica, and the Carboniferous L. Columbiana, the primary 

 chamber is represented by a merely cancellated nucleus.^ 



2. With reference to the finely tubulated proper wall of 

 Eozoon, he has fallen into an error scarcely excusable in an 

 observer of his experience, except on the plea of insufficient access 

 to specimens. He confounds the proper wall with the chrysotile 

 veins traversing many of the specimens, and obviously more 

 recent than the bodies whose fissures they fill. That he does so 



* See Journal of London Gcol. JSoc, January, 1878. 



