14 Prof. H. A. Nicholson — New Devonian Fossils. 



The characters of Callopo^-a incrassata (Fig. 1) are very remark- 

 able, and I am not altogether 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 Meliolites and Fistulipora 

 is sufficiently clear ; but there are many anomalous points presented 

 by the present fossil. The specimens which I have included under 

 this head occur in at least three foi'ms. Some of them form thin 

 crusts upon HeliopJiyllum Halli, Cystiphjllum vesicidosum, or other 

 corals, themselves in turn supporting the tubes of Ortonia or 

 Spirorhis, or the creeping stolons of Aulopora. Others form flat- 

 tened or undulating expansions, supported upon a thin concentrically- 

 wrinkled epitheca. Others, again, form irregular or hemispheric 

 masses, varying in size from an inch in diameter, or less, up to the 

 size of a man's head, and composed of numerous concentric layers. 

 The majority of examples exhibit the singular areolae or clear spaces 

 on the surface, which are neither penetrated by the corallites nor 

 by the tubuli of the coenenchyma (Fig. Ic). These spaces are 

 usually elongated, and often somewhat depressed below the general 

 surface, and prolongations extend from them in a star-like manner. 

 The corallites in their immediate neighbourhood are also usually, 

 some or all, larger than the ordinary ones. Only a few specimens 

 exhibit the large conical perforated eminences above alluded to ; 

 but in those that do, these structures appear to belong properly to 

 the fossil and not to be extraneous. In other minor respects diiferent 

 specimens differ considerably amongst themselves. The examples 

 from the Comiferous Limestone are mostly of large size, the 

 corallites are comparatively small, the intervals occupied by the 

 ccenenchyma are proportionately wide, and the fact that the coenen- 

 chyma is minutely tubular cannot be determined. I feel, how- 

 ever, pretty sure that these peculiarities are to be ascribed to the 

 manner in which the specimens from this formation are fossilised. 

 In the specimens from the Hamilton formation, again, the peculiar 

 vacant areolee cannot always be recognized, and appear to be 

 sometimes absent over considerable areas. Most of the Hamilton 

 specimens show very clearly the tubular character of the coenen- 

 chyma, but there is a good deal of diversity as to its amount. 

 Some examples have the corallites separated by 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 very minute tubuli between. An epitheca 

 is only occasionally present, and the flattened expansions often carry 

 corallites on both sides. 



Locality and Formation. — Comiferous 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. 



Genus Alveolites, Lamarck. 

 Mr. Billings has already recorded six species of Alveolites from 

 the Devonian rocks of Western Canada, four from the Hamilton 

 group, and two from the Comiferous Limestone (Canadian Journal, 



