594 



TRANS. ST. I-OUIS ACAD. SCIENCE. 



Siromaiopora hendei (Nicholson), 



" osieolata (Nicholson), 



Caunopora hudsonica (Dawson), 

 Dictyostoma undtilatum (Nicholson), 

 Coenostoma galtense (Dawson). 



Genus STROMATOPORA (Goldfuss). 

 The characters of this genus, proposed by Goldfuss in 1S26, and 

 followed by DeBlainville and Lonsdale a few years later, are not 

 sufficiently specific to include all the forms that have been placed 

 under the name Stromatopora. Some have regarded the Stro- 

 matoporidcB as a natural group, others as a heterogeneous mix- 

 ture. At any rate, these fossils have been a cause of much 

 discussion as to their zoological affinities : they have been placed 

 amongst Sponges^ Foraminifera^ and even Corals. The two pre- 

 vailing opinions refer them to either Foramlnifera or Sponges. 

 It is not my purpose to discuss this subject, but to point out 

 several forms that occur at Hamilton, in the Niagara formation. 

 These remains characterize various formations from the Upper 

 Cambrian to the Devonian inclusive ; and probably they still ex- 

 isted in the later Carboniferous period, as indicated by some forms 

 found in Missouri. — Many forms occur in Canada, ranging from 

 the Niagara to the Corniferous groups. Those Niagara forms 

 occurring at Hamilton must be referred to several genera or sub- 

 genera. They all consist of lamina?, which were originally cal- 

 careous (in some cases the calcareous matter has been replaced 

 by silica), deposited concentrically on some foreign surface (or 

 around some centre), separated by interspaces through which 

 delicate pillars extend, connecting the lamellar surfaces. The 

 laminae are connected by minute pores giving communication 

 between the interlaminar spaces. Sometimes these pores connect 

 more distant interlaminar spaces by passing through hollow pil- 

 lars. Again, the laminte may be pierced by horizontal or oblique 

 tubes. The surfaces of the mass often show irregular compara- 

 tively large apertures, indicating perforations extending through 

 several interspaces ; but these last, as remarked by Dr. J. W. 

 Dawson, are lined with dense matter, as exhibited in some of the 

 Niagara species. Even though the laminae are mammillated or 

 nodulose in form, the vertical section always appears as stratified 

 layers of more or less rectangular cells, even though the spaces 

 may be partly filled by the thickening of the walls. 



