Fiskerester fra den devoniske sandsten paa Norges vestkyst. 15 



Summary. 



The first discovery of fishremains in the Devonian sandstone 

 formations on the west coast of Norway was made by dr. T. G. 

 Halle on the borders of the Gjegnalund glacier, which lies oppo- 

 site Skjærdalen near Hyen in Nordfjord. The fishremains were 

 here found in loosened blocks together with the Thursophyton flora, 

 which was already known as belonging to this locality. 



The materiel is not extensive and only consists of isolated 

 scales and dermal bones belonging to the heads of two different 

 fishes. The species can therefore not be determined with absolute 

 certainty. The commonest kind belongs to the Osteolepidae, 

 it closely resembles, may possibly be identical to Diplopterus 

 Agassizi Traill. The other kind belongs to the Rhizodontidae 

 and may perhaps be considered to be a Tristichoptherus 

 alatus Egerton. It is at any rate very nearly related to it. They 

 are both well known fishes in the Scottish middle devonian. Diplop. 

 terus is common in the Achanarras Band, which is rich in fish, 

 while Tristichoptherus is the most prevalent in John O' Groats 

 Sandstone Group, which forms the uppermost part of Scotlands 

 Middle Old Red Sandstone, or Orcadian ; the latter is also found 

 in the Orkneys in Eday Sandstone, which appears to be of a 

 similar age to John O' Groats. 



The fish remains fully justify Nathorsts decision of the age 

 of these strata as being Middle Devonian, and brings the develop- 

 ment of our western Devonian still nearer the Scottish. 



If we attempt to find still more parallels, we attain no certain 

 result, as there is some uncertainty as to species, and the two 

 Scotch fishes with which they are most nearly identified, appear 

 at two different horizons separated more than 1800 m. from each 

 other by the mighty Thurso Flagstone Group. Both horizons 

 belong, however, to the upper part of the mighty Orcadian Group, 

 and it, therefore, seems reasonable to suppose that the fish and flora 

 horizon at Svartvand belongs to the upper part of the Middle 

 Devonian. 



Several interesting problems thus arise in connection with 

 the succession of the strata in our western Devonian. 



