Geological Society of London. 369 



With, regard to the systematic position and affinities of Procolophon 

 the author remarked that the presence of two distinct nares shown 

 in his specimens removed the genus from the family Mononarialia, 

 of the Order Theriodontia, in which it was placed by its founder, 

 Prof. Owen. He further discussed in considerable detail the 

 characters upon which the Order Theriodontia is founded, and 

 arrived at the conclusion that this group must be regarded as 

 synonymous with the family Cynodontia, which, with the Dicyno- 

 dontia and Cryptodontia, make up Prof. Owen's Order Anomodontia. 

 The genus Procoloplwn, displaying no distinguishable canines, does 

 not possess the chief character of a Cynodont, and the author pre- 

 ferred to regard it as belonging to a parent type from which the 

 dental modifications of the Anomodontia have been derived, and, 

 from its apparent relationship to Hatteria, as forming an extinct 

 family of the Ehynchocephala. Hence the question arises, whether the 

 Anomodontia and the South- African forms described as Dinosaurs might 

 not be united with the Ehynchocephala to form a subclass of Reptilia. 



4. " On the Microscopic Structure of the Stromatoporidfe, and on 

 Palgeozoic Fossils mineralized with Silicates, in Illustration of 

 Eozoon." By Principal Dawson, LL.D., P.K.S., F.G.S. 



The fossils included in the group Stromatoporidee occur from the 

 Upper Cambrian to the Upper Devonian inclusive, and are especially 

 abundant in the Trenton, the Niagara, and Corniferous formations. 

 The author regards Stromatopora as a calcareous, non-spicular body, 

 composed of continuous, concentric, porous lamina, thickened with 

 supplemental deposit, and connected by vertical pillars, most of 

 which are solid. The surface shows no true oscula ; but perforations 

 made by parasitic animals have been mistaken for such. From the 

 structiire they could not have been related either to Sponges or to 

 Hydractinice, and still less to Corals ; they are truly Foraminiferal, 

 and may be regarded as the Palaeozoic representatives of Eozoon. 

 Stromatopora occurs infiltrated with calcite or silica, or with its 

 structure wholly or in part replaced by crystalline silica or dolomite. 

 The author concluded his first section with the characters of the 

 genera which have been included in the Stromatoporidge. 



]n the second part he noticed a number of facts relating to the 

 occurrence of hydrous silicates, of the nature of serpentine and 

 loganite, infiltrating Palseozoic fossils and illustrating the mode of 

 occurrence and mineralization of Eozoon. Instances of this kind 

 were said to be exceedingly common, showing that such silicates, 

 whether originating as direct deposits from water, or as products of 

 the decomposition of other minerals, are efficient agents in the 

 infiltration of the pores and cavities of fossils, and have played this 

 part from the earliest geological periods. 



5. " On some Devonian Stromatoporidae." By A. Champernowne, 

 Esq., F.G.S. 



The author's object in this note was to give some account of the 

 origin of a fine series of Stromatoporidse presented by him to the 

 Society. They were all from the Great Devon Limestone at Dar- 

 tington, near Totnes, and were obtained from a spot in the Pit Park 



DECADE II. — VOL. IV. — NO. VIII. 24 



