BBITISH UPPEK-SILURIAN FENESTELLIDiE. 241 



16. A Eeview and Description of the various Species of British 

 Upper-Silurian Fenestellid^. By George William Shrub - 

 SOLE, Esq., F.G.S. (Eead February 25, 1880.) 



Plate XI. 



I hayE been recently engaged in investigating some of the Palaeozoic 

 Polyzoa, more particularly the Upper-Silurian Fenestellidgs : the re- 

 sult I beg to lay before the Society. 



The Silurian group of the Fenestellidoe has by no means proved 

 hitherto so interesting a field for research as the Carboniferous 

 series. I find that only three palaeontologists have entered the 

 field — Lonsdale, Portlock, and Prof. ]\I'Coy. The former, in Mur- 

 chison's ' Silurian System,' gives an account of four species of 

 FenesteUa and two allied forms, which are most likely Fenesiellcc. 

 Prof. M'Coy, in the Cambridge Catalogue, describes two more 

 species, and Portlock one from the Silurian strata in Ireland, making 

 nine species in all, viz. : — 



FenesteUa antiqua, Lonsd., Murch. Sil. Syst. pi. 15. fig. 16. 



Milleri, Lonsd., ibid. pi. 15. fig. 17. 



prisca, Lonsd., ibid. pi. 15. figs. 15, 18. 



reticulata, Lo7isd., ibid. pi. 15. fig. 19. 



Ketepora infundibulum, Lonsd., ibid. pi. 15. fig. 24. 

 Gorgonia assimilis, Lonsd., ibid. pi. 15. fig. 27. 

 FenesteUa rigiclula, M'Coy, Brit. Pal. Foss. pi. 1 c. fig. 19. 



patula, M'Coy, ibid. pi. 1 c. fig. 20. 



Gorgonia regularis, Portl., Geol. Londonderry, p. 324, pi. 22. fig. 3. 



Prof. ll'Coy's portion of the work has the advantage of being full, 

 clear, and definite. On the other hand, Lonsdale, from causes to 

 which I shall allude, has not been so fortunate or successful in his 

 descriptions. Indeed the work of Lonsdale in arranging the Fenes- 

 teUce of the Murchison collection can only be regarded as provisional. 

 With the scanty material at his command it could not be otherwise. 

 He says himself on this point, " It is very difficult to establish 

 species from fragments '' *. 



To assist me in the work, I have carefully gone over all Lonsdale's 

 type specimens of FenesteUa, now in the [Museum of the Geological 

 Society, with the result that I can quite confirm what he says, that 

 he had only " fragments " to work from, and those destitute of re- 

 liable specific character. For the most part they are mere frag- 

 ments of the reverse side of the polyzoarium, weathered, showing, 

 of course, no cellules, and altogether valueless for the accurate defi- 

 nition of any species. This state of things accounts for the ambi- 

 guity and generalities in Lonsdale's descriptions ; while the absence 

 of data, such as measurements of interstices, or dissepiments, or 

 number of cellules, as adopted by Prof. M'Coy, renders it impossible, 

 from his text, to distinguish between the various Species. In not 

 one of the Silurian species of FenesteUa described by Lonsdale do 1 

 * Murehison's Sil. System, p. G78. 



