194 



PKOCEEDIffGS OF THE GEOLOGICAL SOCIETY. 



On palceontological grounds this fully confirms the most recent re- 

 searches relative to the absence of the Middle Old Red Sandstone 

 in Scotland and Ireland, and probably in the Welsh area also. 



8 genera and 12 species of Elasmobranchii (Placoidei) range 

 chiefly through the Lower Old Red — many with only 1 representa- 

 tive, viz. Byssacanthus, Oonchodus, Qosmacanihus, Ctenacanthus f 

 OtenoptycJdus, and Paregcus ; also Onchus with 4 and Ptychacanthus 

 with 2 species. The remaining 114 species represent 9 families and 

 41 genera, all Ganoidei : — 







Genera. 



Species. 



1. 





. 2 



2 



2. 





3 



10 



3*. 





15 



40 



4. 





, , 1 



4 



5. 





, . . 8 



23 



(3. 





3 



9 



7. 





, 2 



2 



8. 





1 



1 



0. 





, , . 6 



23 







41 



114 



The Lower Old Red is represented by 36 genera and 85 species, 

 and the Upper by 15 genera and 25 species ; and I know of no 

 species that is common to the Old Red Sandstone proper and the 

 Carboniferous group above. 



Those genera that seem to specially characterize the Upper Old 

 Red Sandstone, chiefly Scotch, are Actinolepis, Asterolepis, Boihrio- 

 lepis, Cosmacanthus, DendrodusfGlyptolcemus, Glyptopomus, Holopty- 

 cldus (some species), Homothorax, Lamnodus, Pamphr actus, Phanero- 

 pleurus, and Phyllolepis* . The 2 genera (?) and 2 species (?) in the 

 so-called Middle Old Red tend also to show, through physical re- 

 search, that no such grouping exists. 



56 genera and 150 species, other than British, have been recog- 

 nized in Europe and America, but are allied through about 40 

 genera, or that number is common to all three areas, America, the 

 British Islands, and Europe. 



Of the entire British Devonian and Old Red fauna (544 species) 

 we have seen that 32 genera and 51 species pass to the Carboniferous. 

 I give the number of species in the classes that connect the two 

 epochs : — 



* Dr. Traquair is now engaged in carefully revising and describing the 

 Ganoid fishes of the Old Red Sandstone. They could not be in better hands ; 

 few men are so competent to undertake so large a task. Many names are only 

 provisional. 



