loo The Irish Naturalist. 



ON THE FKNKSTKIvIvID^, WITH REFKRKNCE TO 

 IRISH CARBONIFEROUS STRATA. 



BY GRKNVII,I.E A. J. COLK, M.R.I. A., F.G.S. 



Professor of Geology in the Royal College of Science for 



Ireland. 



In the present preliminary paper, I can do little more than 

 call attention to the beauty and variety of a family of fossil 

 polyzoa, the remains of which are widely distributed across 

 Ireland. The Fenestellids are among the commonest fossils 

 wherever the great Carboniferous Limestone retains traces of 

 organic remains ; members of the famil}^ are figured in almost 

 every text-book of geology ; and the reticulated character of 

 their funnel-shaped or spreading zoaria renders their detection 

 easy, even on rough surfaces of the rock. 



The family, which was a favoured one in the days of Sir 

 Richard Griffith and Frederick M'Coy, has suffered in recent 

 years from the criticism of Mr. G. W. Shrubsole^, who has 

 been able largely to reduce the number of species of the type- 

 genus Fenestclla. His papers, we should note, do not deal with 

 the '* Fenestellidse," as ordinarily understood, but with 

 Fenestellc^ only ; and they show how species have been 

 founded, not only upon imperfect specimens, but upon the 

 characters of different portions of the same zoarium. 



However, Mr. Shrubsole's method of dealing with the super- 

 ficial markings and accessory parts of the Fenestellid zoarium 

 was, to say the least, drastic and indiscriminate, and formed 

 a marked contrast to the careful observation expended upon 

 these details on the other side of the Atlantic. It may fairly 

 be said that Mr. H. A. Prout, Professor James Hall, and Mr. 

 E. O. Ulrich have taught us much of the beauty of our own 

 fossil polyzoa ; and the abundance of material in our 

 Carboniferous strata is surely sufficient to rouse us now to 

 emulation. 



The delicate outer structures of polyzoan colonies are bCvSt 

 preserved in shales ; but a great deal can be learned from the 



^ " A Review of the British Carboniferous FenestelHdae," Quart, /ouj-n. 

 Geol.Soc. London, vol. xxxv. (1879), p. 275; "A Review and Description 

 of the various species of British Upper-Sihirian FenestelHdse," ibid., 

 vol. xxxvi., p. 241 ; " Further Ncrtes on the Carboniferous Fenestellidae," 

 ibid., vol. xxxvii., p. 178. 



