MINERALS AND GEOLOGY OF CANADA. 509 
4 2. Stenopora fibrosa (= Chetctes lycoperdon) Fig. 73. This form 
Fig. 73. 
punctured surface (the openings of the cells), and their delicately 
fibrous structure. Very common throughout the Trenton Group, 
Utica Slate, and Hudson River Group of the Lower Silurian Series. 
Found also in the Upper Silurian rocks. 
3. Favosites Gothlandica (= F. Niagarensis) Fig. 74.~-The 
ismade up of long fibrous or acicular 
tubes, with numerous transverse dia- 
phragms. These latter, however, tobe 
properly seen, require the aid of a 
magnifying glass. _ The corallum is 
either globular, hemispherical, dendri- 
tic, or irregular. The dendritic forms 
often resemble sea-weeds, but, except in 
much weathered specimens, a magnify- 
ing glass will generally show their 
corallum in this species is properly hemispherical 
and sometimes of large size, but specimens are 
generally obtained in the form of irregular masses. 
These are made up of hexagonal or polygonal 
cell-tubes with numerous transverse diaphragms, 
and with pores in the cell walls. They are 
” 
the ‘‘ petrified honeycombs 
Principally Upper Silurian ; 
in the Lower Silurian and frequently in the Devonian Scries. 
4. Michelinia convexa, Fig. 75.— The 
corallum in this species consists of large but 
shallow polygonal cells, with 
part vesicular diaphragms, and pores in cell 
walls. Devonian strata, Canada West. 
of quarrymen, &e. 
but found occasion- Fg 74. 
convex and in 
5. Halysites catenulatus (= Catenipora escharoides), fig. 76.—In 
this species, the well-known “chain coral,’’ the 
oval cell-tubes are united in chain-like groups. 
There are numerous diaphragms, and some rudi- 
mentary radiating-lamellee. 
istic of the Clinton and Niagara group (Upper 
Chiefly character- 
Silurian), but found also of late years in the 
Lower Silurian series. 
