19 1 1. No. 7. A NEW DOWNTONIAN FAUNA OF THE KRISTIANIA AREA. 13 



III. The upper horizon with PJujUocnr'Kh. Kurt/pfends and f i s h es 

 or the fish-horizon, about 9.; m. up. 



IV. The upper horizon with trails, about 16 m. up. 



These horizons can also briefly be denoted b\- the number I— IV. 



The New Fauna. 



Fossils are found, as can be seen, in several horizons of this section, 

 but it is however, principally in the upper iiorizon with PltyUocarids^ 

 Eunjpterlds and fishes that I have discovered a series of really de- 

 finite forms. On the other hand, fossils are quite commonly found in 

 this horizon in an unusually fine state of preservation, and so far as 

 concerns several forms, quite commonly as complete or nearly complete 

 specimens. This is especially the case with fishes, since here the softest 

 parts of the body, which usually have entirely disappeared, have been 

 discovered preserved in all details in many specimens. This circum- 

 stance renders my material particularly interesting from a palæontological 

 point of \ie\v. 



The new fauna, which I have discovered consists entirely of Plujllo- 

 cayidt<, Eurypieridit, and Ostracoderm fishes. Of the last mentioned I 

 discovered two forms of the strange CepludaspidomorpJii and three forms 

 of the beautiful Anaspida. As regards common marine animals, no trace 

 was discovered. We are therefore evidently considering a freshwater 

 fauna, and this fact fully agrees with the nature of sediments. 



The said Crustacea and cephalaspidomorph fishes are, as is known, 

 not unfrequent in brackish water- and fresh water- facies in the upper- 

 most part of the Silurian and in Devonian. 



Anaspid fishes, on the other hand, are \ery rare forms, hitherto 

 only found in two areas. Some years ago they were at first found in 

 the uppermost part of the Scotch Silurian, from which part TrA(1UAIK 

 has described the two genera Birkcnia and Lasa)nus. Subsequently 

 A. S. Woodward described the third genus Kiiphancropx from the 

 Upper Devonian at Scaumenac Bay in Canada. Only one single badly 

 preserved specimen of this last form is known. To this interesting order 

 of very ancient fishes I am now able to add three new genera. In 

 a great abundance of forms this order seems to have been of more 

 consequence than has been presumed, among the fresh water fishes in 

 the uppermost part of the Silurian. 



