108 G. R. VINE OX PHYLLOPORA AND THAMXISCT7S FROIT THE 



15. Notes on Species of PhtllopoPvA and TiiAirxiscTJS from the 

 Lower Silueiax Eocks near Welshpool, Wales. By George 

 Robert Vine, Esq. Communicated by Prof. P. Martin Duncan, 

 P.R.S., P.G.S. (Read December 17, 1884.) 



Mr. G. W. Shrubsole, in a paper " On the Occurrence of a new- 

 Species oi Phyllopora in the Permian Limestone"*, remarks that 

 *" the genus Phyllopora has as yet been but imperfectly worked ; its 

 rarity in the more recent and its imperfect preservation in the older 



rocks go far to account for this In the Lower Silurian rocks 



Phyllopora is most abundant. There are at least two distinct species, 

 if not more. The preservation of the remains in these beds is most 

 unfavourable for exact work, occurring, as they often do, in coarse 

 ash or shale, and distorted by cleavage." 



In the collection of the School of Mines there were t several 

 specimens of Phyllopora catalogued and labelled as such, which I 

 was allowed to examine when collecting material for my Second 

 British Association Report on Possil Polyzoa. The specimens from 

 the Lower Llandeilo rocks are the common forms, generally 

 designated Eetepora by early authors. One specimen is in the 

 Wyatt-Edgell collection, and we have only the reverse aspect of the 

 form ; but in places where the branches are worn the cells can be 

 seen, not sufficiently, however, to enable us to make out their cha- 

 racter. The fenestrge are oval or irregular, branches anastomosing, 

 consequently without dissepiments. 



In the Caradoc series of fossils of the same collection, several 

 specimens are labelled, and also catalogued, as Phyllopora Hisingeri^ 

 M'Coy, and one, belonging to the Wyatt-Edgell collection, is cata- 

 logued as P. ornata, MS. Generally speaking, all these forms are very 

 indistinct or ill-preserved. In a box with one specimen (y^^ Case V) 

 labelled Phyllopora"^. Hisingeri, M'Coy, a small portion of the 

 zoarium of Rdepora cellulosa, Linne, is placed for the purpose of 

 comparison. The Lower Silurian fossil is from Robeston Wathen, 

 Pembrokeshire. I have several specimens of P. Hisingeri, M'Coy, 

 in my cabinet ; for it is the most common of all the forms found in 

 the Caradoc or Bala beds ; but it is only by careful manipulation, and 

 adjustment of light, that the cell-structures of these species can be 

 made out ; and even then not much dependence can be placed on the 

 diagnosis. In the Lower Llandovery beds one specimen is marked 

 and catalogued (op. cit. p. 64) as Phyllopora, sp. Besides these I 

 have no other knowledge of species of the genus found in the 

 Lower Silurian rocks in Britain sufficiently characteristic to be 

 individualized. 



In the beginning of August, 1884, Mr. J. B. Morgan, of Welshpool, 



* Quart. Journ. Geol. Soc. vol. xxxviii. pp. 347, 348. 



t In 1881. See Catalogue of Mus. Pract. Geol., Cambrian and Silurian 

 fossils, 1878. 



