2 Mr. A. S. Woodward on the 



As already remarked by Prof. Lankester, the fish-remains 

 extend the eonclusions of the Swedish geologists*, and prove 

 that two distinct horizons — an Upper and a Lower — are recog- 

 nizable in the Devonian formation of Spitzbergen. Some of 

 the rocks of the lower division are indistinguishable from 

 certain red sandstones, grey micaceous sandstones, and corn- 

 stones occurring in the Lower Old Red Sandstone series of 

 the west of England. The fish-bearing horizon of the upper 

 division is a compact and dark-coloured clayey ironstone. 



I. Fish-Fauna of the Lower Devonian. 



Subclass OSTRACODERMI. 



Order II E T E RO ST II AC L 



Family Pteraspidse. 



Genus Pteraspis. 



Being known only by ventral shields and fragments, the 

 generic determination of the Pteraspidians from Spitzbergen 

 is only provisional. Most probably, however, the remains 

 are referable to the type geims, Pteraspis. 



Pteraspis Natliorsti (Lankester). (PI. II. fig. 1.) 



1884. Scaphaspis Nathorsti, E. R. Lankester, Kongl. Svenska Vetensk.- 

 Akad. Ilandl. vol. xx. no. 9, p. 5, pi. i. figs. 1-3. 



As remarked by Lankester, the ventral shield of this species 

 seems to have been slightly broader and shorter than the 

 typical form met with in the Herefordshire cornstones, and 

 it is readily distinguished from all known species by the 

 feeble beading and crimping of the surface-ridges. Assliown 

 by one specimen (PI. II. lig. 1), the obtusely rounded median 

 extension of the posterior end of the shield is also charac- 

 teristic. On the visceral aspect the hinder border seems to 

 exhibit a faint thickening, and there is a feebly marked 

 median tubercle immediately in advance. 



Form, and Loc. Red ^licaceous Ir'aiulstono and Cornstones, 

 Dickson Bay ; Grey Tilestone, Klaas Billen Bay. 



Pteraspis, sp. ind. 

 Some specimens of the red sandstone from Liefde Bay are 



* A. E. NoixkMiskiiild, " Sketch of the (took\!ry of Ice Sound and Doll 

 Sonnd, SpitzbergtMi," (iool, Mag. [2] vol. iii. (18'7()). pp. 10-l!-"{. 



