62 
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layers, superimposed one upon the other. Corallites very minute, tubular, their circular cali- 
ces slightly elevated above the general surface, and surrounded by a prominent margin, 
From three to five calices in the space of one line, separated by intervals of from half to two- 
thirds of their own width. Corallites, sometimes with the theca undivided, but more com- 
monly partitioned off by a few remotely placed horizontal tabule. Ccenenchyma composed 
of exceedingly minute tubuli, which are partitioned off by numerous close-set horizontal diaph- 
ragms. No traces of septa. The surface exhibits at intervals of about two lines elongated, 
star-shaped spaces, sometimes smecoth, sometimes punctate or minutely pitted, which are not 
penetrated by tubes of any kind, and appear to be quite solid. There are generally from three 
to six corallites surrounding these vacant spaces, which are larger than the others ; and the 
spaces themselves have a long diameter of about a line or more, by.a shorter diameter of half 
a line. In some specimens, also, the surface exhibits occasional large conical elevations pierced 
each by a single canal, the diameter of which is about a line, and which descends vertically 
into the mass. . 
The characters of Callopora incrassata are most remarkable, and I am not satisfied that 
two closely related species have not been included under the above description. That we have 
to deal here with a Tabulate coral allied to 
Fistulipora or Heliolites is sufficiently clear ; but 
@:® b there are many anomalous points presented by 
ea 8 the fossil, The specimens which I have included 
OC under this head occur in at least three forms. 
"©: © Some of them form thin crusts upon Heliophyl- 
o®) ° lum Halli or Cystiphyllum vesiculosum, them- 
selves in turn supporting the tubes of Ortonia 
or Spirorbis, or the creeping stolons of Awlopora. 
Others form flattened or undulating expansions, 
and others appear as irregular or hemispheric 
masses, varying from an inch in ‘diameter or 
less, up to the size of a man’s head, and com- 
posed of numerous concentric layers. The 
majority of examples exhibit the extraordinary 
clear spaces on thesurface,which areneither pene- 
trated by the corallites nor by the tubuli of the 
ccenenchyma. These spaces are usually elon- 
Fig. 19. gated, and often somewhat depressed below the 
Callopora incrassata, (Nich). a, A fragment, natural general surface, and prolongations extend from 
cz. portion ofthe surface magmied bowing theealiees them in a starlike manner. The corallites in 
highly magnified showing a vacant space surrounded by coral- their immediate neighbourhood are also usually, 
lites. d. Vertical section of a fragment enlarged. From tl 
Hailiongeup oo  .  epome or all, larger than the jordinanyeanmess 
Only a few specimens exhibit the large conical elevations perforated by large vertical canals ; 
but in those that do, these structures appear to belong properly to the fossil, and not to be 
extraneous. In other minor respects the fossils differ very considerably amongst themselves. 
The specimens from the Corniferous Limestone are mostly of large size, the corallites are of 
comparatively small size, the intervals ocupied by the ccenenchyma are proportionately wider, 
and the fact that the ccenenchyma is composed of minute tubuli can not be determined. I feel, 
however, pretty sure that these peculiarities are simply to be ascribed to the method in which 
the specimens from this formation have been fossilised. In the specimens from the Hamilton 
formation, again, the peculiar vacant spaces are not always recognisable, and appear to be cer- 
tainly absent in some instances over areas of considerable extent. Most of the Hamilton 
specimens show very clearly the tubular nature of the coonenchyma, but there is a good deal 
of difference as to the amount of coonenchyma. Some examples have the corallites separated 
by intervals of nearly their own width, the interspaces being filled with circular or polygonal 
tubules. Others, on the other hand, have the corallites nearly in contact, with but a single 
row of exceedingly minute tubuli separating them. An epitheca, so far as I have seen, is 
only occasionally present, and the flattened expansions often sarry corallites on both sides. 
Locality and Formation.—Corniferous Limestone of Port Colborne, and more abundantly 
in the same formation at Hagersville. Common in the Hamilton formation at Widder, and 
also at Bartlett’s Mills, near Arkona, in the Townships of Bosanquet and South Williams. 
