HISTORICAL INTRODUCTION. 9 



In 1853, Steiningcr (' Gcognostische Beschreibung der Eifel ') described a 

 Stromatoporoid from the Devonian Limestones of the Eifel under the name of 

 Stromatopora foliata, referring the genus to the Sponges. 



Two species of Stromatopora were also described by Fr. Ad. Romer in the 

 1 Palaeontographica ' (Bd. iii, 1852, and Bd. v, 1855) under the names of 

 S. patella and 8. polymorpha, var. stellifera. The true nature of these forms is, 

 however, uncertain. 



The two Sandbergers (' Die Versteinerungen des rhcinischen Schichten- 

 systems in Nassau,' p. 380, 1850 — 56) express the opinion that the genus 

 Stromatopora should be referred to the Polyzoa, but they base this view upon the 

 untenable supposition that the " radial pillars " served for the lodgment of zooids. 



The same view as to the affinities of Stromatopora is expressed by Prof. Ferd. 

 Roemer (' Lethaea Geognostica,' 3rd ed., vol. i, p. 166, 1851 — 56), who compares 

 the genus with the recent Gellepora. In a note, however, Roemer adds that he 

 has since examined specimens of S. polymorpha from the Eifel in which he can 

 detect both prismatic tubes and tabulae, and that it will be therefore necessary to 

 remove the genus Stromatopora to the Tabulate Corals, and to place it in the 

 vicinity of Chaitetes and Favosites. This last conclusion was really based (as 

 subsequently pointed out by Roemer himself, ' Lethaea Palasozoica,' p. 460, 1883) 

 upon certain singular corals (Ghcetetes stromatoporoides, Roemer), which commonly 

 have their surface covered by an encrusting Stromatoporoid. 



In 1857, Mr. Billings founded the genus Beatricea for the reception of certain 

 extraordinary fossils from the Ordovician and Silurian Rocks of North America 

 ('Geological Survey of Canada; Rep. of Progress for 1856,' p. 343, 1857, and 

 e Canadian Naturalist,' new ser., vol. ii, 1857). Mr. Billings at first held the 

 opinion that Beatricea was probably referable to the vegetable kingdom. It will 

 be shown subsequently, however, that the affinities of this remarkable genus are 

 probably with the Stromatoporoids, though the structure of the skeleton is highly 

 anomalous. 



In 1858, Magister Friedrich Schmidt described two species of Stromatoporoids 

 from the Silurian Rocks of Esthonia (' Silurische Formation von Ehstland, Nord- 

 Livland und Oesel,' p. 232). One of these he identified with Stromatopora 

 striatella, d'Orb., and the other he described as S. mammillata, n. sp. The latter 

 is really the previously described Clathrodictyon striatellum, d'Orb. 



In 1860, Eichwald (' Lethaea Rossica,' vol. i, p. 345) defined Stromatopora as a 

 spongy mass, composed of closely approximated lamellae, and enveloping other 

 organic bodies ; its surface being covered with minute rounded pores arranged 

 without order over the whole surface of the skeleton. He seems to have been the 

 first to promulgate the view, afterwards supported by von Rosen, that the skeleton 

 of the Stromatoporoids consisted of a network of homy fibres, which had been 



