46 



Thus, it is not uncommon to meet with colonies, in which the great majority of the coral- 

 lites have a diameter one and a half lines, whilst some few have a diameter of a line or a 

 little less. 



Whilst the mural pores are usually in two rows, there is sometimes but a single row, and 

 sometimes three rows ; and single colonies may be found to combine all these variations in 

 different corallites. It is probable that the typical forms upon which Groldfuss founded his 

 species F. basaltica, as believed by Lonsdale and McCoy, are truly referrible to specimens of F. 

 Gothlandica, (Lam), in which but a single row of pores is present. F. Goldfussi Edwards and 

 Haime, again seems unquestionably to be nothing more than a variety of F. Gothlandica 

 as asserted by Mr. Billings, the only distinctive characters brought forward by its authors 

 being the unreliable ones that the rows of pores vary from one to three, and that they are 

 more closely approximated than in typical examples of the latter. Lastly, the elevated ring 

 which is often found surrounding the pores in F. Gothlandica, is in many cases absent, single 

 specimens often exhibiting both conditions. It may be added that the pores themselves, even 

 in specimens otherwise well preserved, can by no means universally be detected. 



The tabulae are for the most part complete, extending from one side of the theca to the 

 other ; but this condition of parts is by no means constant. Specimens, otherwise well pre- 

 served, sometimes exhibit a complete absence of the tabulae, the corallites being hollow. 

 Others exhibit a condition of things similar to what occurs in Fawsites Forbesi, though not so 

 marked. .The inner surfaces, namely, of the corallites, exhibit rudimentary and imperfect 

 tabulse, in the form of little projecting lamella? or ridges which project into the cavity of 

 the theca. Specimens exhibiting this peculiarity can usually be distinguished from examples 

 of F. Forbesi, without difficulty, by the fact that the ridges representing the tabulse are not so 

 closely set, are more delicate and plate like, usually run across the whole width of the corallite, 

 and do not give to the interior of the theca the extraordinary roughness of appearance which 

 is characteristic of F. Forbesi. In other specimens, again, the tabulae have the characters 

 which are distinctive of F. hemispherica, being closely set and incomplete, often more or less 

 bent, and commonly interlocking. Such specimens, however, are readily separated from those 

 which are rightly referred to F. hemispherica, by the fact that in the former some of the coral- 

 lites are always found to exhibit the complete tabulae of F. Gothlandica, whilst the size of the 

 corallites is on the average much more considerable. In fact, the commonest condition in the 

 specimens here alluded to, is that alternating portions of the mass exhibit the complete tabulse 

 characteristic of F. Gothlandica, and the incomplete tabulae characteristic of F. hemispherica. 

 Mr. Billings has also pointed out that the same corallite sometimes exhibits complete tabulae 

 in one portion of its course and incomplete tabulse in another. 



As to the condition of the septa, the diagnosis of the species would, perhaps, be altered 

 for the better by the statement that as a general rule the septa are absent, or at any rate are 

 indeterminable. They are, however, not uncommonly to be recognised in the form of small 

 inequalities or minute tubercles on the interior of the walls of the corallites ; and they some- 

 times exist in the condition of distinct spines, though I have never noticed this state of things 

 in any of the specimens from the Corniferous Limestone. It is, however, not uncommon in 

 Silurian specimens, and it has been observed and figured by Mr. Billings from Canadian 

 examples found in the Corniferous. 



Adult colonies of F. Gothlandica usually have the form of much depressed pyriform 

 masses, but great variations exist in this respect and young colonies are usus lly spheroidal 

 or simply pyriform, whilst the largest and oldest masses tend to assume the form of dome- 

 shaped or hemispheric masses. The colony is based upon a concentrically wrinkled epitheca, 

 which is very commonly wanting in decorticated specimens, and attains a considerable thick- 

 ness in aged examples. 



Locality and Formation. Common throughout the Corniferous Limestone in Canada 

 West, and also in the Hamilton formation. 



48. FAVOSITES BASALTICA (Goldfuss). 



Calamopora basaltica (Goldfuss), Petref. Germ. PL XXVI. Figs. 4a, 4d 



Favoeites basaltica; (Billings), Canadian Journal, New Series, Vol. IV. p. 106, (in part). 



It is with regard to this species that I find myself compelled, though with great diffi- 

 dence, to differ from the conclusions arrived at by Mr. Billings (Canadian Jour. Vol. IV. p. 



