﻿Gryptozoon and other Ancient Fossils. 205 



concentric lines, in well-preserved specimens, is traversed 

 by numerous minute irregular canals, which branch and 

 anastomose without regularity. The central portions of 

 the masses are usually filled with crystalline, granular 

 and oolitic material, and many specimens show the 

 intrusion of these extraneous and inorganic substances 

 between the concentric laminae." 



In general form the masses are hemispherical or Ijroadly 

 turbinate, and the layers are concave upward as if they 

 had grown from a central point or circle and expanded 

 very rapidly in ascending, the general result resembling a 

 series of bowls one within another. The larger masses 

 are from one to two feet in diameter. 



Thin slices, from specimens kindly presented to the 

 Peter Kedpath Museum by Prof. Hall, show that the 

 primary laminae are thin and apparently carbonaceous, as 

 if originally of a corneous or membranous character, and 

 they are usually finely crumpled as if by lateral pressure,-^ 

 while they can occasionally be seen to divide into two 

 laminae with intervening coarsely cellular structure. The 

 thick intermediate layers which separate these primary 

 laminae are composed of grains of calcareous, dolomitic and 

 silicious matter, in some specimens with much fine car- 

 bonaceous material. This last, under a high power in thin 

 slices, is seen to present the appearance of a fine network 

 or stroma in which the inorganic particles are entangled. 

 The canals traversing these intermediate layers appear to 

 be mere perforations without distinct walls, and are filled 

 with transparent calcareous matter, which renders them, 

 under a proper light, sufficiently distinct from the grey 

 granular intermediate matter which they traverse. So 

 far as observed, the canals are confined to the intermediate 

 layers, and do not seem to penetrate the primary laminae, 

 though these sometimes present a reticulated appearance 



1 This may, however, represent an originally corrugated structure of the laminae. 



