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CHAPTER II. 
CORALS OF THE CORNIFEROUS AND HAMILTON FORMATIONS. 
Of all the organic remains of the Devonian Rocks of Canada, and especially of the 
Corniferous Limestone, none are more conspicuous than the Corals, whether we take into 
consideration the vast number of individuals or the great variety of type which they exhibit. 
Mary parts of the Corniferous Limestone are almost wholly made up of corals ; and as these 
are usually silicified, they weather out of the limestone in a most beautiful manner, and can 
be obtained in a state of exquisite preservation. The soft shales of the Hamilton group, also, 
are often charged with the remains of corals, which, from the decomposition of the surr.und- 
ing matrix, can be obtained perfectly clear of adhering sediment. Mr. Billings in his admir— 
able memoir upon the fossil corals of the Devonian Rocks of Canada West (Canadian Journal, 
New Series, Vol. V., p. 251), estimates the number of corals in the Corniferous and Hamilton 
formations as probably about eighty, and of these he describes no less than fifty-four. Some 
of the most striking of these forms, such as the species of Phillipsastrea, have not come under 
my notice in any portion of the Corniferous Limestone or Hamilton Group studied by me; 
but I shall here describe over seventy species which have come under my personal observation. 
Of these, thirty-one belong to the 7abulata, five are referable to the Tubulosa, and thirty-five 
belong to the great group of the Rugosa, The genera represented are twenty-one in number, 
viz.: Favosites, Alveolites, Michelinia, Syringopora, Fistulipora, Chetetes, Callopora, Striatopora, 
Trachypora, Aulopora, Zaphrenti’s, Microcyclus, Blothrophyllum, Clisiophyllum, Heliophyllum, 
Diphyphyllum, Eridophyllum, Amplexus, Cystiphyllum, Haimeophyllum and Petraia. Of the 
species about twelve can certainly be identified with known European species, viz.: Fwvosites 
Gothlandica, F. hemispherica, F. Forbesi, &. polymorpha, F. dubia, F. cervicornis, PF. reticulata, 
Aulopora tubeformis, Diphyphyllum gracile, Heliophyllum Halli, Cystiphyllum vesiculosum and 
Michelinia convera. Besides these well known forms, there are others which are very closely 
allied to Huropean species, and some which may perhaps turn out, upon fuller investigation, 
to be nothing more than varieties. 
Genus BLOTHROPHYLLUM (Biilings). 
Gen. Char.—“ Corallum simple, turbinate or cylindrical. Internal structure consisting 
of a central area occupied by flat transverse diaphragms, an intermediate area with strong 
radiating septa, and an outer area in which there is a set of imperfect diaphragms projecting 
upwards, and bearing on their upper surfaces rudimentary radiating septa. A thin complete 
epitheca, and a septal fossette”’ (Billings). 
The central spaceof the theca in corals of this genus is occupied, as in Amplerus, by flat or 
slightly flexuoustabulze, upon which the septa do not encroach. Outside this central area isanar- 
row zone in which the tabulze are bent downwards towards the base of the corallum, and are 
at the same time sometimes split and bifurcated, whilst the continuity of the spaces between 
them is interfered with by a series of strong septa, Outside this again is an outer zone, 
formed by a series of tabula, which are directed upwards and outwards in an arching manner, 
and which carry on their upper surfaces a series of imperfect septa, their lower surlace being 
simply costate or ridged. Lastly, the arched tabule of this external zone are covered by a 
thin but strong epitheca with which the outer surface of the coral is invested. The genus dif- 
fers from Zaphrentis in not haying the septa prolonged inwards to, or near to, the centre, and 
in having the central tabulate area surrounded by a partially vesicular zone and an exterior 
zone composed of arched tabulee and imperfect septa. From Amplexus it is distinguished by 
the possession of the external area Jast mentioned, and by the septa being more largely de- 
veloped; whilst it is distinguished from Clisiophyllum by the first of the above-mentioned 
peculiarities, and also by the fact that the tabule of the central area are flat or slightly flexu- 
ous, and are not elevated into a conical protuberance. 
The genus Blothrophyllum was originally defined by Mr. Billings (Can. Jour., New 
Series, vol. iv., p. 129) and the single species B. decorticatum was described. In addition to 
this previously recorded and very characteristic species, I have now to describe another allied 
form, &. approximatum, also from the Corniferous Limestone of Western Ontario. 
