74 THE ROYAL SOCIETY OF CANADA 



The oldest portion has been designated the Paradoxides lamel- 

 latus substage or zone, as being characterized by the P. lamallatus 

 of Hartt and its accompanying fauna. The rock here is a very fine 

 grained gray shale and is in marked contrast with the coarse sandy 

 shales of the Protolenus zone which underlie it. Its texture indicates 

 slow deposition in placid waters. Here we are able to make use of 

 trilobites as markers of special zones of life. There are two char- 

 acters that mark these early forms of trilobites which are less pro- 

 nounced in those of the substage above ; one is the wrinkled or ridged 

 surface of the test in most of the species, the other is the presence 

 of prickles or spines on the surface of others. 



The genus Liostracus appears in this early substage. The writer 

 has limited this name of Angelin to such Ptychoparoid species as had 

 smooth tests and are devoid of genal spines; this is the case with L. 

 ouangondianus, Hartt, which is our representative of the L. aculeatus 

 of Angelin, the type of the genus. But a more striking member of 

 this genus is L. tener of Hartt, notable for the prominent curved ridges 

 on the fixed cheeks and correspondingly elevated eyelobes. For many 

 years we had thought that this form was peculiar to America, but a 

 representatives of it was found some years ago in the Cambrian strata 

 of the Montaigne Noir in the south of France by Mons. Jean Miquel, 

 who has done important work in elaborating the Cambrian faunas of 

 the south of France. 



Of the Conocryphinae, typical genera of the Lower Paradoxides 

 beds* two forms are found in this early subzone, viz, Conocoryphe 

 Walcotti allied to C. Baileyi, Hartt, of the subzone above, but with a 

 smoother and thinner test; and Ctenocephalus Matthewi, Hartt var. 

 perhispidus. The former shows the thin flexible test marking many 

 of the species of this subzone, the latter the very hispid surface of 

 other species. 



Passing to the Brachiopods and Gasteropods we find a variety 

 of small thin shelled species, none of which play an important role 

 in the fauna, and there are some Phyllopods and Ostracods. 



ETEMINICUS SUBZONE. 



But it is in the next member of the St. John Group that we are 

 in the presence of a full and varied fauna of the Paradoxides beds. 

 In this subzone the slate is of a coarse texture and the fossils in some 

 places have been rolled together, forming calcareous nodules, abound- 

 ing with the disjointed skeletons of numerous animals, chiefly trilobites, 



*Hence Angelin, the Swedish palaeontologist, called this zone the Region of the 

 Conocoryphees. 



