PALAEOZOIC TERRANE BENEATH CAMBRIAN. 53 



Adding to the Etcheminian fauna of Newfoundland that of 

 southern New Brunswick we have the following forms (macro- 

 scopic) : 



species. Species. 



Hyoliihes 2 



Orthotheca 4 



Urotheca n. gen.. i 



Aptycopsis I 



Kutorgina (?) i 



Obolella i 



O bolus I 



Coleoides i 



Hyolithellus 2 



Helenia i 



PalceacDKxa i 



Scenella 2 



Platyceras 3 



Modiolopsis i 



Platysolenites (?) i 



Coral-like forms (Protozoans), fragments of Cystidians and bur- 

 rows and trails of marine worms, including Arenicolites and 

 Psammichnites. 



The uniformity of conditions attending the depositions of the 

 Etcheminian terrane throughout the Atlantic Coast province of 

 the Cambrian is surprising, and points to a quiescent period of 

 long continuance during which the Hyolithidse and Capulidse 

 developed so as to become the dominant types of the animal 

 world, while the Brachiopods, the Lamellibranchs and the 

 other Gasteropods still were puny and insignificant. The Crus- 

 tacea so far as we know, were represented only by one Phyllo- 

 carid and the trilobites so far have not been recognized at all. 



Dana has said that " if strata should be found containing no 

 Trilobites, but only Worms, the lower types of Brachiopods, 

 Ostracods among the Crustaceans, and other, inferior species, a 

 place in the Cambrian would properly be made for it.'" To the 

 author it appears that while a place might for convenience be 

 found in the Cambrian for such a fauna, it would not be "prop- 

 erly found," if W'C regard its biological significance. To assign 

 such a fauna to the Cambrian would be to ignore the impor- 

 tance of the trilobites in distinguishing from each other the sev- 

 eral life-zones of the Cambrian system ; we would not recog- 

 nize as Cambrian a varied fauna from which the trilobites 

 were absent. 



1 Manual of Geology, 4th ed., pp. 487-488. 



