3 



from a point below, while the convex surface is on the lower 

 side. A careful examination of the nature of these bodies 

 proves that, while having the concentric structure common to 

 Stromatopora, they have not the regular succession of layers 

 of tubuli characteristic of the species of that genus and cannot 

 properly be included under that term. I therefore propose 

 the term Gryptozoon as a designation for this peculiar form 

 and mode of growth which will be more fully elucidated in 

 the future." 



Hall recognized but one species (Gryptozoon proliferum) ,. 

 which he denned in the following terms : — 



"These bodies are made up of irregular, concentric 

 laminae of greater or less density and of very unequal thick- 

 ness. The substance between the concentric lines, in well- 

 preserved specimens, is traversed by numerous, minute, ir- 

 regular canaliculi which branch and anastomose without 

 regularity- The central portion 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. That 

 these are intrusions and not inclusions, is shown from the 

 fact that they can be traced to a vertical fissure or break 

 leading to the exterior of the fossil, and which allowed the 

 crystalline matter to enter." 



Sir William Dawson examined specimens from the type 

 locality and has published ( 3 ) the following additional observ- 

 ations : — 



"Thin slices, from specimens kindly presented to the 

 Peter Redpath Museum by Professor 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 siliceous matter, in some 

 specimens with much fine carbonaceous 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 inter- 

 mediate 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 



(3) Note on Gryptozoon and other Ancient Fossils. Canadian 

 Record of Science, vol. vii., No. 4 (October, 1896), p. 205. 

 b2 



