1903.] Account of Pahieospondylus Gunni, Tmqv.air. 99 



suspensory apparatus, which may represent the palato-quadrate and 

 hyo-mandibular elements. The branchial arches are wholly unlike 

 anything seen in Marsipobranchs, but call to mind the similar 

 structures in the Dipnoi and larval Amphibians. The dorsal side of 

 the skull shows a large cranial cavity with thin vertical walls, but no 

 complete roof, a pair of auditory and a pair of nasal capsules. The 

 eye was situated over a structure which resembles a sub-orbital bar, 

 but which is sub-divided into a hyo-mandibular and palato-quadrate 

 clement. At the anterior extremity of the skull are processes which 

 may be compared with the rostal processes of Elasmobranchs. The 

 vertebrae are cyclo-spondylous, with large neural arches. 



The organism was evidently a primitive fish, with some features 

 which are suggestive of Marsipobranchs, some of Elasmobranchs, and 

 some of young Dipnoi or larval Amphibians ; after branching off from 

 the Piscine stem, at a point below the origin of the Elasmobranchs, it 

 pursued an independent course of development. 



The substance of which the fossil consists is a true coal : Coccosteus. 

 is sometimes similarly preserved, and an analysis of the latter, kindly 

 made by Mr. J. E. Marsh, M.A., yielded the following results : 



Carbon 68-4 



Hydrogen 4-5 



Oxygen (by difference) 11-3 



Ash 15-8 



100-0 



Abstracting the ash, the residue closely resembles in composition an 

 ordinary non-caking coal, such as that of South Staffordshire, as will 

 be seen from the following table : 



Coal from Non-caking 



Coccosteus. Coal. 



Carbon 81-1 79-39 



Hydrogen 5 -3 5-36 



Oxygen (by difference) 13*6 15-25 



100-0 100-00 



The skeleton of Coccosteus also occurs in a different state of 

 fossilisation : in this the organic matter has disappeared, leaving a 

 mineral residue, in which the original structure is preserved, and may 

 be recognised as that of bone. Thus definite proof is afforded of a 

 transformation, previously suspected, by which bone may be converted 

 into coal. 



