igiÖ. Xo. lO. THE LOVVER CAMBRIAN HOLMIA FAUNA. IO9 



easy to decide, as none of the Scandinavian Mcsomicidae are found in 

 North America. 



Our Hohnia fauna are now compared by Walcott with the North 

 American Callavia fauna, which in his opinion, are found in a zone 

 high up in the Lower Cambrian, but are older than the t\pical Olenellus 

 fauna, in the highest zone. He further states regarding this subsequently 

 that in Scandinavia there must apparently be an interval in the succession 

 of strata between the zones with Holmia Kjernlfi and Paradox. Olandicus, 

 which may represent part of the succession of strata between Olenellus and 

 Holmia in Nevada. This is strengthened b}- the fact that Olenellus, which 

 in North America is very characteristic of the upper part of the Lower 

 Cambrian, is not found in Scandinavia. 



In my opinion this view can hardly be correct. 



We also parallel the Scandinavian Holmia fauna with the Callavia 

 fauna, but assume that both must be accepted as contemporary with the 

 typical Olenellus fauna. 



As far as we have been able to discover, indeed, a profile has never 

 been found in N. America in which an Oleuella zone succeds above a 

 Callavia zone; the latter is far more often superimposed in the Atlantic 

 province by the Protolenus fauna, which must be regarded as a complete 

 transition fauna between the Lower and the Upper Cambrian or even as 

 belonging to the lowest part of the Middle Cambrian ^ 



Walcott is therefore compelled to accept that the Olenellus zone in 

 the classic profiles in New Foundland and New Brunswick are represented 

 by a bed devoid of fossils lying between the said fossil-bearing zones-. 

 This is of course possible, but in my opinion it is more likely that the 

 Callavia and Olenellus fauna are of the same age (vicarious). This view 

 is supported by the the fact that a number of important forms are common 

 to both. It may also be stated that Walcott ^ recently found in the Robson 

 Peak district Callavia forms that are much more pimitive than Callavia 

 Brøggeri in the Atlantic province, together with such a typical Olenellus 

 as 01. Tmemani Walcott. 



' The latter is emphasized by several American scientists, (Grabac, X. American Index 

 Fossils, Vol. II, page 6061. As however all the Paradoxidae are lacking-, and forms 

 that belong to the Strettnetla genus or are very close to it play a ver\' important part, 

 it would appear equalK" naturally to classify the Protolenus zone as the uppermost 

 part of the Lower Cambrian or as a transition zone (pag. 45I. 



'^ Smith Sound Section, Manuels Brook Section, and Hanford Brook Section. iCh. Wal- 

 cott, Lower Cambrian Terrane in the Atlantic Province, Proc. Wash. Acad. Sc. 

 Vol. I, 1900, page 301.) 



3 New Lower Cambrian Subfauna iSmithson Misc. Co'.!. Vol. 57. No. 11, 1913». 



