5 
characteristic of the species, very thick and compact walls, thick tabulae, 
and septa extremely ill-defined, may be due to this phenomenon and be 
superimposed on some more delicate structure. One of the topotypes of 
C. canadensis Bill, kindly lent by the Canadian Geological Survey (G.S.C. 
1136a) showed that it, too, was very recrystallized, with quartz needles, 
calcite, and much dolomite. Practically all the structure was obscured, the 
walls were thick — as thick as in a typical Lyopora — the septa indetermin- 
able, and even the pores, so characteristic of this genus, were extremely 
rarely seen. By these sections alone this specimen could be compared only 
with Lyopora favosa; but there is no doubt at all that the correct identifi- 
cation is C. canadensis Bill., for the surface features of the corallum and 
weathered interior of the corallites can be seen, in this case, just sufficiently 
well for comparison to be made with undoubted C. canadensis. 
This shows the extent to which structure can be obscured by recrystal- 
lization, and it is probable that L. favosa, were it differently preserved, 
would show considerably more detailed structure. It is far from impossible, 
even, that it is related to Calapoecia. An interesting fact in this con- 
nexion is that Calapoecia is not found in Scotland at all. Until further 
evidence is forthcoming the genus Lyopora Nich. and Ether, cannot be 
included in Calapoecia Billings, and must be considered in the light of 
Kiaer’s work (1929) w^hich is the most recent comprehensive study of it. 
For although it is possible that in the cases of the recrystallized Calapoecia 
and L. favosa similar structures are being obscured, it is just as probable 
that dissimilar structures are masked and two different forms are unnatur- 
ally made to appear similar. 
SPECIES AND VARIETIES 
Altogether, seven species of Calapoecia have been described: C. canaden- 
sis, C. huronensis, and C. anticostiensis by Billings (1865) ; C. amphigenia 
Lindstrom (1880) ; C. borealis Whitfield (1900) ; C. favositoidea Savage 
(1913); and C. arctica Troedsson (1928). Included in these by the 
synonymy (5ee below) are Columnopora cribriformis Nicholson (1874), 
Houghtonia huronica Rominger (1876), and Columnopora rayi Davis 
(1887). 
Whiteaves in 1897 (157, 8) combined C. canadensis, C. huronensis, 
Columnopora cribriformis, Houghtonia huronica, Rominger, and also 
“ Hemispherical masses of Syringopora D. Dale Owen (1852) ” under the 
names Calapoecia canadensis. The reference to Dale Owen (page 181) can- 
not be verified as he gives no figures or descriptions. Whiteaves (158) 
followed the opinion of Nicholson that C. anticostiensis was a Syringo- 
phyllum. Lambe’s revision of the genus (1899, 45) makes all these species, 
including C. anticostiensis, but not Owen’s Syringopora, synonyms of C. 
canadensis. 
Unfortunately Lambe’s conclusions have been fairly generally disre- 
garded and a confusion of nomenclature has continued until the present. 
Billings (1865, 426) distinguished his C. huronensis from C. canadensis by 
saying “ it is closely allied to C. canadensis, but has the corallities, in gen- 
eral, more slender, and presents a different aspect.” From his descriptions 
his comparison can be carried farther: C. huronensis has corallites with a 
diameter of less than one line and smaller corallites between them, either 
