8 BRITISH STROMATOPOROIDS. 



In 1847, Hall (' Pal. New York,' vol. i, p. 48, pi. xii) founded the genus 

 Stromatocerium for a Stromatoporoid from the Trenton Limestone of North 

 America, the structural characters of the genus, however, being left undefined. In 

 the same work (vol. ii, p. 135, 1852) Prof. Hall states that, according to his 

 observations, the skeleton of Stromatopora is " composed of minute cylindrical 

 tubes with considerable space between, and that the laminated structure arises from 

 thin layers of calcareous matter deposited and filling the spaces between, and 

 enclosing the tubes." He considers the genus to be referable to the Corals, and to 

 be " more nearly related to Tubipora than to any other genus." 



In the ' Prodrome de Paleontologie ' (1850), d'Orbigny places the genus 

 Stromatopora among the Sponges, and names a number of new species, all of 

 which, however, are founded upon forms previously described by other writers. 

 For the Wenlock Stromatoporoid which Lonsdale had erroneously referred to S. 

 concentrica, Goldf., he proposed the name of 8. striatella ; and Tragos capitatum, 

 Goldf., is removed to Stromatopora as S. capitata. On the other hand, 8. poly- 

 morpha, Goldf., appears under the guise of no less than five new species, 

 distributed partially under Stromatopora and partially under the new genus 

 Sparsispongia (viz. Stromatopora Goldfussii, 8. sulcata, Sparsispongia polymorpha, 

 8. radiosa, and 8. ramosa). Lastly, Actinostroma (Stromatopora) verrucosum, Goldf., 

 is taken as the genuine Stromatopora polymorpha of Goldfuss. 



In the subsequently published 'Cours Elementaire de Paleontologie' (1851), 

 d'Orbigny again expressed the opinion that the Stromatoporoids are referable to 

 the Sponges. 



In 1851, Prof. M'Coy expressed the opinion ('Brit. Pal. Foss.,' p. 12) that 

 Stromatopora is a true Coral allied to Fistulipora and Ileliolites (Palwopora) . His 

 definition of the genus is : " Corallum calcareous, forming large amorphous 

 masses composed of very thin superficial layers of minute vesicular tissue of the 

 thickness of one cell each, occasionally marked on the upper surface with 

 extremely obscure, distant, quincuncially-arranged small pits." 



In a later portion of the same work (p. 65) M'Coy described, unfortunately 

 only partially with figures, several species of British Stromatoporoids. The forms 

 which he identified as Stromatopora concentrica, Goldf., and S. polymorpha, Goldf., 

 cannot now be certainly determined without an examination of the original speci- 

 mens. The former would seem from the description given to be an Actinostroma, and 

 the latter is apparently a true Stromatopora. The genus Gaunopora of Phillips is 

 regarded as a subgenus of Stromatopora, Goldf., and three species are referred to 

 it, viz. G. placenta, Lonsd., G. ramosa, Phill. (Brass. MS.), and G. verticillata, 

 M'Coy. The last of these three is a remarkable Devonian fossil, which seems to 

 be really identical with the Stachyodes ramosa of Bargatzky, from the Devonian 

 Limestones of the Paffrath district. 



