102 THE CANADIAN NATURALIST. [April 



occurring only at rare intervals (figure 3). The larninse them- 

 selves are excavated on their sides into rounded pits, and 

 are in some places traversed by canals, or contain secondary 

 rounded cells, apparently isolated. In addition to these general 

 appearances, the substance of the laminas, where most perfectly 

 preserved, is seen to present a fine granular structure, 

 and to be penetrated by numerous minute tubuli, which are 

 arranged in bundles of great beauty and complexity, diverging in 

 sheaf-like forms, and in their finer extensions anastomosing so as 

 to form a net-work (plate, figures 2 and 4). In transverse sections, 

 and under high powers, the tubuli are seen to be circular in outline, 

 and sharply defined (plate, figure 5). In longitudinal sections, 

 they sometimes present a beaded or jointed appearance. Even 

 where the tubular structure is least perfectly preserved, 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 structure. On 

 the contrary, their aspect is that of matter introduced by infiltra- 

 tion, 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 ser- 

 pentine 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 laminas have in places a crystalline 



rower and thinner ones, and finally to the irregularly aggregated mode 

 of growth, designated by Dr. Carpenter as accrvuliiw, is well seen. 

 The white patches in the upper portion of the figure do not arise from 

 any imperfection in the electrotype, but represent the irregular growth 

 of this part of the calcareous skeleton.— T. S. H.J 



