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



whereaa in tlie latter species there are interspersed numerous exceed- 

 ingly minute calices amongst those of ordinary size. From the well- 

 known Chaetetes tumidus, of the Carboniferous rocks again, the 

 present species is distinguished by the polygonal shape of the calices, 

 their thin walls, and their much larger size ; the corallites of the 

 former being thick-walled and nearly circular, and there being about 

 eight of them in the space of one line. 



Locality and Formation. — Not rare in the Hamilton Group at 

 Widder, Township of Bosanquet. 



Chaetetes qtjadeangularis, Nicholson. PI. IV. Fig. 8. 



Spec. char. — Corallum forming exceedingly thin crusts of from 

 one-tenth to one- sixth of a line in thickness. Corallites sub-equal, 

 with very thin walls, about eight in the space of one line, for the 

 most part polygonal, but often quadrangular in shape. The surface 

 is smooth, and destitute of eminences, nor are there groups of larger 

 corallites regularly interspersed amongst the smaller ones. 



Chaetetes quadrangularis is found commonly encrusting Selio- 

 phyllum Halli and Cystiphyllum vesicidosum, and often forming expan- 

 sions of considerable extent. The crusts, however, are of excessive thin- 

 ness, and are apparently never composed of more than a single layer 

 of corallites. It is distinguished from G. tid)erculatus, Edw. and H., 

 to which it is most nearly allied, by the tenuity of the crusts, the 

 smaller size of the corallites, the absence of distinct eminences or 

 gibbosities of the surface ("niamelons"), and the very commonly 

 quadrangular form of the calices. 



Locality and Formation. — Not uncommon in the Hamilton shales 

 of Bartlett's Mills, near Arkona, township of Bosanquet. 

 Genus Heliophyllum, Hall. 



The genus Heliophijllum, is particularly well represented in the 

 Devonian rocks of Canada, no less than nine species having come 

 under my notice as occurring in rocks of this age. Of these, six 

 species, viz. H. Halli, H. Canadense, H. Eriense, H. Hayugaense, H. 

 exiguum, and H. colligatum, have been recorded and described by 

 Mr. Billings (Canadian Journal, new series, vols. iv. and v.), and 

 one species, viz. H. Colhornense, has been described by myself. All 

 these species occur in the Corniferous Limestone, JI. Halli alone, so 

 far as at present known, passing on into the Hamilton group. I 

 have now, however, to record from this last-mentioned formation one 

 apparently new species of this genus, together with another from the 

 Corniferous Limestone. 



Heliophyllum sub-c^spitosum, Nicholson. PI. IV. Fig. 9. 



Spec. char. — Corallum small, simple or compound, cylindrical, or 

 slightly expanding towards the calice. Arched striae upon the flat 

 sides of the septa, and spines upon their free edges, placed at distances 

 of from a third to a quarter of a line apart. Calice oval or circular, 

 shallow. Septa apparently sixty in number, at a diameter of eight 

 lines. Epitheca with numerous annulations and constrictions of 

 growth. Occasional individuals, with the other characters of the 

 species, appear to be simple; but the majority of examples increase 

 by the production of lateral buds. The new corallites thus pro- 



