94 JOHAN KIÆR. M.-N. Kl. 



the Hypoparia- Agraulos series, in a similar manner to that of the Norwe- 

 gian Middle Cambrian form that was described by Brøgger as Ellipsoce- 

 phalus ci renins. (Page 51.) 



None of these genera can therefore be accepted as the desired transi- 

 tion forms. 



Walcott's interesting genus Alhcrtella (upper beds of Lower Cambrian) 

 and ZacantJioidcs (Middle Cambrian j^ in my opinion for similar reasons 

 cannot be descendent from the Mesonacidac, but may conceivably have 

 developed from the Paradoxides stock at a much earlier period, by which 

 the remarkable mixture of primitive and far advanced characters is most 

 easily explained. 



As we see, in my opinion we know practically nothing of the Para- 

 doxides stock in its earliest stages of development (Lower Cambrian). Our 

 knowledge merely provides us with the latest stages in a number of 

 different lines of development, the earlier stages of which are still un- 

 discovered. We must assume that this first differentiation and development 

 took place in regions the sediments of which have not yet been investi- 

 gated, or which can no longer be investigated, having been removed by 

 subsequent erosions or covered by the sea or younger beds. 



As in so many other cases of palaeontological research we must recog- 

 nize that the preservation of the evolution of the organic world is extre- 

 mely defective, and that in consequence our knowledge is very disconnected; 

 yet who can say; it may be that a fortunate discovery even in the near 

 future may throw a clearer light upon these questions. 



Stratigraphical Section. 



Having described the various forms found in the Lower Cambrian beds 

 at Tømten, we will in conclusion deal with the stratigraphical occurrence 

 of the fauna, and its relation to our other Lower Cambrian strata. 



I. The Stratigraphical Occurrence of the Fauna. 



As we repeatedly have pointed out, the fossils described in this work 

 do not all appear in the same strata at Tømten. Some are found in the 

 typical Hohuia shales, others on the other hand appear to be connected 

 with the sandy limestone that occurs in a higher niveau. 



' Ch. Walcott, Cambrian Trilobite?, 1908, (Sjmiths. Misc. Coll., LIII, No. 2). 



