Fearnsides, Elles, Smith — Palceozoic Rocks of Tomer oy. 121 



PAL^ONTOLOGICAL APPENDIX. 



Graptolites. 



Some of the Graptolites whose names appear in our lists have not 

 hitherto been recorded from any localities in Great Britain or Ireland 

 (J/, acinaces, M. nohilis^ &c.) ; they have, however, been so recently 

 described and figured by Professor Tornquist, of Sweden, that fuller 

 notes upon them would be superfluous. 



Others, again (Climacograpti), have been recently described in 

 Part V. of the Monograph of British Graptolites (Palseontogrophical 

 Society), while a few appear to be new to science. These will be 

 described in the forthcoming parts of the same publication. 



Trilohifes. 



There are several points of interest in the Trilobites of the 

 Desertcreat group, especially as regards the specimens found in the 

 Killey Bridge beds. Many of these, it is true, are well-known forms ; 

 but these are accompanied by others whose occurrence appears to be 

 unique ; and though many of them were noticed by Portlock in his 

 Report, a few notes may serve to bring his descriptions up to date. 



These notes are based, not only upon specimens found by ourselves, 

 but also upon the specimens in the collections of the Geological 

 Survey ; and our thanks are due to Dr. Teall, Director of the Survey, 

 for permitting us to examine them. 



Trinucleus concentricus Eaton. 



The true T. concentricus does not seem to be present at Pomeroy. 

 It is, however, represented by several varieties which differ from it in 

 that the glabella in each case encroaches upon the punctate margin of 

 the head-shield, and shows signs of incipient furrows at the base. 

 In each variety the pygidium is alike, and similar to that of the 

 typical form. 



Yar. Portlockii Salt. 



Glabella pyriform, prominent, encroaching slightly upon the border 

 of the head-shield ; furrows indistinct or absent. 

 Cheeks about as along as broad. 



Border^ punctate, not folded as in T, concentricus, but lying in 

 one plane. 



Three rows of punctures in all in front of glabella, tending to 

 become confluent in a radial direction. 



It is noteworthy that the appearance of the punctate border varies 



