ICI I. No 7. A NEW DOWNTONIAN FAUNA OF THE KRISTIANIA AREA. 2 I 



of their relationship to the Scotch and Enghsh species of a genus that 

 is so common both in Ludlow and Downtonian. 



In addition to Crustacea, the fauna comprises new forms of ana- 

 spid and cephalaspidomorph fishes as mentioned above. 



Anaspid fishes, as is well known, have been found principally in 

 the Downtonian of Scotland, but one species — Euplianerops — has been 

 discovered in the Upper Devonian of Canada. This interesting group 

 thus lived at any rate from the last part of the Upper Silurian to the 

 upper Devonian period. As the two new Norwegian forms do not 

 entirely agree with the Scotch forms, but constitute a new group, the 

 anaspid fishes recently discovered do not provide sufficient data to allow 

 of any definite conclusions regarding geological age. 



The two forms of CephalaspidomorpJn which are to be seen in the 

 new fauna are of greater consequence in this respect. As previously 

 stated these form phylogenetical links between the Downtonian Atele- 

 aspis and typical forms of CepJialaspis, which are conmion in Lower 

 Devonian, but occur even in the passage beds to this formation. It is 

 therefore probable, that the strata, in which the Norwegian forms have 

 been found, are of Downtonian age. We therefore arrive at the same 

 result as in the case of the Crustaceans. 



In consequence of these facts is seems quite certain, that a parallel 

 can be made between the lower part of the sandstone series in Ringe- 

 rike with its fossiliferous horizons and the uppermost part of the Upper 

 Silurian in Scotland and England, the so called Downtonian. I am 

 inclined to believe, that most probably it should be compared with 

 the middle part of this series (Downtonian). Though this is a question 

 which cannot be dealt with in this preliminary report. 



There is therefore good reason for believing that since the whole 

 sandstone series in the Kristiania area forms a continuous series without 

 unconformity, the whole series belongs to the youngest division of the 

 Upper Silurian, or in other words, is older than the Devonian formation. 

 This also agrees with the fact that our sandstone series has been aftected 

 by the Caledonian earth movement, which took place in Scotland be- 

 tween the Upper Silurian and the Devonian. Neither does the thickness 

 of the sandstone oppose this theory, since the Downtonian series in 

 Scotland is often of much greater thickness. 



Former estimates of the age of the sandstone are there- 

 fore incorrect. We can say with absolute certainty that the 

 lower part of this formation is of Upper Silurian (Down- 



