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wmm 



mmmmmm 



■I I 



58 



Canadian Record of Science. 



wholly dissolved out and its place occupied with pyrite. It 

 is to be observed, however, that in fossil sponges the si'.i- 

 cious matter has not inti-equently been dissolved out, and 

 its space left vacant or filled with other matters. I have 

 specimens of Astylosponjia from the Niagara formation 

 which have thus been replaced by matter of a ferruginous 

 color ; and in a bundle of fibers, probably of a sponge allied 

 to Hyalonema from the Upper Llandeilo of Scotland ('nee 

 named Hyalostelia by Hinle'), I find the substance of the 

 spicules entirely gone and the spaces formerly occupied by 

 them empty. It should be added that joints of Crinoid 

 stems and fronds of Fenestella occurring in the same speci- 

 men with the Uphantaenia are apparently in their natural 

 calcareous state." 



The type of structure of Cyathophycus is essentially that 

 of the Hexactinellid sponges of the sub-order Bictyonina of 

 Zittel, and under this, as has already been suggested by 

 Barrois, it belongs to the family of Bictyospongidce, estab- 

 lished by Hall for Dictyophyton and the allied sponges of 

 the Erian rocks. This type, already known as far back as 

 the Utica slate, is now carried a stage farther by our 

 discoveries at M^tis. 



f 



While the above paper was in the press, Dr. Selwyn was 

 80 kind as to send to me for inspection, through Mr. Ami, 

 of the Geological Survey, some slabs of gray and dark 

 coloured shale from the Quebec group rocks of the Chau- 

 di^re Eiver, in which spicules of sponges had been detected 

 Bome years ago, by Mr. T. C. Weston and Mr. Willmot of 

 the Survey, but which have not been published. The spe- 

 cimens show two forms of cruciform spicules, one with very 

 slender rays and as much as a centimetre in measurement 

 from point to point, the other stouter and measuring about 

 five millimetres in extent, and therefore more nearly resem- 

 bling those of Protospongia tetranema. There are also long 



' I have similarly explained Pyritonema of McCoy and Eophyton 

 expkmatum of Hicks, as has Hinde also, in Geol. Maga., 1886. 



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