4Q2 NATURAL SCIENCE. j UNE> 



examined large series of sections of nummulites may observe in these 

 fossils : and the tubuli are often filled with dolomite or calcite very 

 difficult to distinguish from the substance of the calcareous lamina. 



The authors of the paper refer (p. 272) to the late Dr. Carpenter 

 as having failed to distinguish the chrysotile veins from the proper 

 wall ; but when in England, not long before his lamented decease, I 

 had the pleasure of going over his collection of slices with him, and 

 of ascertaining that he quite understood the distinction between the 

 veins of asbestiform serpentine and the organic structures. At that 

 time he hoped to have prepared an exhaustive memoir on the subject, 

 including my material as well as his own. Had he been permitted to 

 fulfil this intention, many subsequent mistakes might have been 

 avoided. Even his collections, though varied and admirable, are, in 

 a case of this kind, of comparatively little value without their skilled 

 interpreter, so full of varied knowledge. 



The writers of the paper do not. seem to notice that in the 

 St. Pierre specimens the fine canals and tubuli are often filled with 

 transparent dolomite, difficult to perceive without very good prepara- 

 tions and properly managed light, but of extreme beauty when these 

 conditions are fulfilled. In roughly prepared specimens, indeed, and 

 without careful attention to illumination, these delicate structures are 

 often quite invisible. I have sections properly prepared which show 

 the finest and most complicated tubulation in a manner equal to any- 

 thing I have seen in any fossil foraminifera from more recent 

 formations; while other slices cut from the same specimen, but possibly 

 slightly heated or subjected to mechanical jars in polishing, show 

 little except the curdled appearance of the serpentine and a multitude 

 of cleavage planes in the calcite. In like manner in preparing 

 decalcified specimens, a little heat or an acid too strong or not quite 

 pure, may remove all the dolomitic casts of tubuli, and may erode 

 those of serpentine. From causes of this kind I fear many who have 

 pronounced very decided opinions on Eozoon have not actually seen 

 perfect examples of its structure. 



While, therefore, I must agree with the writers of the paper that 

 their specimens from Somna belong to the category of those banded 

 structures found in concretions and geodes, and at the lines of contact 

 of igneous and aqueous rocks, which are not unfamiliar to those who 

 have advocated the organic origin of Eozoon, and which they have all 

 along been solicitous to distinguish from it, I must emphatically deny 

 that they resemble either in composition, mode of occurrence, or 

 form and structure, the Laurentian Eozoon of Canada. The present 

 writer, indeed, regards it as little complimentary to his long 

 experience of rocks and fossils to suppose him guilty of the error of 

 judgment implied in such a resemblance, and, therefore, begs to say 

 that had he been privileged to examine the now celebrated specimen 

 from Somna in the British Museum, or had he seen such things in 

 the escarpment of that old volcano, or had his friend Dr. Johnston- 



