250 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



future geologists under a debt of gratitude by throwing so much 

 light on a once very obscure big chapter in Scottish geology. 



PLATE IX. 



iSuhprio'uiodus sicbserratus, new species. 



The spike extends but a short way below the beam. Next it 

 there are five .saw-looking teeth. The beam is long and sharp- 

 pointed, more than half of it being without teeth ; Fig. 43. 



Locality. — Fardingmulloch, near Sanquhar; in chert-shale. 



Subprioniodus distans, new species. 



In the beam there is a notch on the under side. The five 

 curving teeth are placed somewhat apart, the last one being set 

 very obliquely to the beam ; Fig. 44. 



Locality. — Fardingmulloch, near Sanquhar, in red Arenig shale. 



Subprioniodus acutus, Smith. 

 Fig. 45. Compare this figure with Fig. 24, PI VI. Fig. 4 5 is from 

 a specimen from Fardingmulloch, near Sanquhar, in chert-shale. 



Subprioniodus calcarus, new species. 



The spike extends a short distance below the beam, and on 

 its under part has a small spur. The long spike carries four 

 teeth set at a short distance apart ; Fig. 46. 



Locality. — Fardingmulloch, near Sanquhar; in chertnshale. 



S ubprioniodus falcatus, new species. 



From about the middle the beam bends down a bit, and then 

 sweeps up into the spike. It carries six small teeth in two 

 groups of three each; Fig. 51. 



Locality. — Morroch Bay; in red Arenig shale. 



Subprioniodus Jardingensis, new species. 



The spike projects slightly below the beam. The beam is 

 curved, and carries nine teeth — four next the spike being long, 

 and four next the end of the beam short, there being a very long 

 tooth close beside them; Fig. 47. 



Locality. — Fardingmulloch, near Sanquhar, in red Arenig shale. 



Subprioniodus crassus, new species. 

 A curved beam carries two stout teeth, the spike being also 

 stout; Fig. 48. 



Locality- — Fardingmulloch, near Sanquhar; in chert-shale. 



