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 sili- 
cious matter has not infrequently been dissolved out, and 
its space left vacant or filled with other matters. I have 
specimens of Astylospongia 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which have thus been replaced by matter of a ferruginous 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 (since 
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 Dictyonina. of 
Zittel, and under this, as has already been suggested by 
Barrois, it belongs to the family of Dictyospongide, 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 Métis. 
While the above paper was in the press, Dr. Selwyn was 
so 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- 
diére River, in which spicules of sponges had been detected 
some 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 
1T have similarly explained Pyritonema of McCoy and Hophyton 
explanatum of Hicks, as has Hinde also, in Geol. Maga., 1886. 
