On the Structure and Position of Eozoon Ganadense. 297 



the gemmation of new segments ceased at that point; and 

 that if new segments be still budded-off, they detach them- 

 selves, so as to lay the foundation of new Globigerince. On the 

 other hand, in the large discoidal Gycloclypeus of the coast of 

 Borneo, which attains a diameter of 2J inches, the number 

 of segments formed by continuous gemmation must be many 

 thousand. 



It is a fact of no little interest, that we have another 

 example of the comparatively gigantic development of the 

 Foraminiferal type in what would have been formerly accounted 

 the earliest fossiliferous rocks. Some years since, Mr. Salter, 

 then the Paleontologist to the Geological Survey of Great 

 Britain, showed me some fossil remains which he had 

 received from the Silurians of Canada, and asked my opinion 

 respecting them. My reply, after a not very detailed exami- 

 nation of them, was to this effect : — " If it were not for their 

 gigantic size, I should say that they were internal casts of an 

 Orbitolite." Having subsequently received additional speci- 

 mens of these fossils, and having carefully compared them 

 with my description of the genus Orbitolites in the Philoso- 

 phical Transactions for 1855, Mr. Salter felt himself justified 

 in identifying them with that type ; and published an account, 

 of them (under the designation Receptaculites) with excellent 

 illustrative figures, in the First Decade of Canadian Organic 

 Remains. Now the largest recent Orbitolite I have seen is. 

 about the size and thickness of a shilling ; whilst the Canadian 

 Receptaculites attains a diameter of twelve inches and a 

 thickness of a third of an inch ; and if this had increased by 

 vertical as well as by horizontal gemmation, piling up its. 

 chambers in successive tiers like' the recent Tinoporus or 

 the fossil Orbitoides, it would have formed a mass equalling 

 Eozoon in its ordinary dimensions. 



Remains of Eozoon are not by any means confined to- 

 Canada. The serpentine marble of Tyree, which forms part 

 of the Laurentian system on the West of Scotland, and a 

 similar rock in Skye, when subjected to minute examination, 

 are found to present a structure clearly identical with that of the 

 Canadian Eozoon. And the like structure has been discovered 

 by Mr. Sanford in the serpentine marble of Connemara, well 

 known to ornamental builders under the name of ' ' Irish green." 

 I have examined several pieces of this rock by placing them in 

 dilute acid, and have not the smallest hesitation in identifying 

 the residuum with the acervuline portion of the corresponding 

 residuum of the Canadian Eozoon, shown in the upper part 

 of the Uncoloured Plate : I have not, however, met with 

 anything corresponding to the lamellated structure shown in 

 the lower part of that plate. Moreover, I find, in place of a 



