40 Fossil Fishes. 



throw no light upon the structure of the tail, the lower part of 

 the individual being wanting. It, however, renders it almost 

 certain that the species cannot be comprehended in the genus 

 Eurynolus as described by Agassiz, and it will not unlikely 

 prove the representative of another new genus. 



It has of late years been generally admitted that the sand- 

 stone from which these fishes are derived is of much later date 

 than the old red sandstone, to which it was once referred, and 

 these remains confirm this belief. The Talceonisci of Europe 

 have never been found below the coal measures, while they ex- 

 tend upward to the copper slate of the zcchstein or magnesian 

 limestone. In the case before us, we find a species of Palceo- 

 niscus accompanied by a fish, the structure of whose tail ap- 

 proaches that of the Pholidophorus, and of other fishes never 

 found below the lias. This fact would seem to imply for this 

 formation, even a higher situation in the series than that which 

 is now assigned it by geologists. A careful and extended ex- 

 amination of the fossil fishes of this deposit, undertaken by able 

 and experienced naturalists, is much needed, and would pro- 

 bably decide the question of its relative age. 



