52 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 23, 



structure is least perfectly presei-ved, traces of it can still be seen in 

 most of the slices, though there are places in which the laminae are 

 perfectly compact, and perhaps were so originally. 



Faithful delineations of these structures have been prepared by 

 Mr. Horace Smith, the artist of the Survey, which will render them 

 more intelligible than any verbal description. 



With respect to the nature and probable origin of the appearances 

 above described, I would make the following remarks : — 



1. The serpentine and pyroxene which fill the cavities of the cal- 

 careous matter have no appearance of concretionary structiu'e. On 

 the contrary, their aspect is that of matter introduced by infiltration 

 or as sediment, and filling spaces previously existing. In other 

 words, the calcareous matter has not been moulded on the forms of 

 the serpentine and augite, but these have filled spaces or chambers 

 in a hard calcareous mass. This conclusion is further confirmed by 

 the fact, to be referred to in the sequel, that the serpentine includes 

 multitudes of minute foreign bodies, while the calcareous matter is 

 uniform and homogeneous. It is also to be observed that small 

 veins of carbonate of lime occasionally traverse the specimens, and, 

 in their entire absence of structures other than crystalline, present a 

 striking contrast to the supposed fossils. 



2. Though the calcareous laminae have in places a crystalline 

 cleavage, their forms and structures have no relation to this. Their 

 cells and canals are rounded, and have smooth walls, which are occa- 

 sionally lined with films apparently of carbonaceous matter. Above 

 all, the minute tubuli are different from anything likely to occur in 

 merely crystalline calcspar. While in such rocks little importance 

 might be attached to external forms simulating the appearances of 

 corals, sponges, or other organisms, these dehcate internal structures 

 have a much higher claim to attention. Nor is there any improba- 

 bility in the preservation of such minute parts in rocks so highly 

 crystalline, since it is a circumstance of frequent occurrence in the 

 microscopic examination of fossils that the finest structures are 

 visible in specimens in which the general form and the arrangement 

 of parts have been entirely obliterated. It is also to be observed 

 that the structure of the calcareous laminae is the same, whether the 

 intervening spaces are filled with serpentine or with pyroxene. 



3. The structures above described are not merely definite and 

 uniform, but they are of a kind proper to animal organisins, and more 

 especially to one particular type of animal life, as likely as any other 

 to occur under such circumstances ; I refer to that of the Rhizopods- 

 of the order Foraminifera. The most important point of difference 

 is in the great size and compact habit of growth of the specimens in 

 question ; but there seems no good reason to maintain that Forami- 

 nifera must necessarily be of small size, more especially since forms 

 of considerable magnitude referred to this type are knoA-^oi in the 

 Lower Silurian. Prof. Hall has desciibed specimens of Beceptacidites 

 12 inches in diameter ; and the fossils from the calciferous formation 

 of Labrador, referred by Mr. Billings to the genus Archmocyatlius, 

 are examples of Protozoa with calcareous skeletons, scarcely inferior 



