Generic Characters.-Corallum dendroid, or forming pyriform convex or depressed hemispherical masses, composed of polygonal slender corallites, which are divided transversely into numerous compartments by complete or incomplete diaphragms. Walls, with one or more rows of circular pores forming communications between contiguous cells. Radiating septa, represented by series of small tubercles or short spines.

The genera Emmonsia, of Edwards and Haime, and Astrocerium, Hall, appear to be identical with Favosites.

FAVOSITES GOTHLANDICA (Lamarck).

This species, which no doubt should be regarded as the type of the genus Favosites, was established, as its name implies, upon specimens procured from the island of Gothland, in the Baltic Sea, where it occurs in a coralline limestone, that is known to be the equivalent of the Wenlock rocks of England, and of the Niagara group on this continent. Although more abundant, and more often quoted by geologists, than any other species, yet we know of no palæozoic coral concerning which there exists so great a diversity of opinion. Indeed, so variously has it been defined by the best authors, that, without much comparison and fusing of differences, it is hardly possible to show that it includes any of our Devonian specimens. The following are the descriptions of several of the leading paleontologists:

1st. GOLDFUSS. Petrefacta Germaniæ, Vol. I., p. 78; Pl. 26, Fig. 3a, 3b, 3c, 3d, 3e, 4d, 4 c.

This distinguished author describes the species as being globular or placentiform, with prismatic tubes either sub-equal or with smaller ones interposed; transverse diaphragms flat; communicating pores in

two rows.

He does not give any measurements, and we are therefore obliged to rely upon his figures for the dimensions of the tubes. They are as follows:-In fig 3 a, which is generally admitted to be a very characteristic form of the species, the tubes are, upon an average, one and a half lines in diameter, some of them being two lines and others only one line. This is important, because, as we shall see hereafter, the species is described by several paleontologists as having the cells only one line wide, upon an average. In this figure two rows of pores are represented, those of the same series being distant from each other

about half a line. In general they are opposite, but in some places those of one row alternate with those of the other. In fig. 3 e, which represents a portion of the specimen a little enlarged, the pores are placed alternately, and surrounded by a narrow elevated rim. The faces of the tubes exhibit a few scattered tubercles, which, according to Edwards and Haime, represent the radiating lamellæ in a rudimentary state. In fig. 3 c, the average width of the tubes is about one and a quarter lines, and in 3 d, the same. In 4 c, which Goldfuss refers to F. basaltica, most of the tubes are one and a half lines in diameter, with a few very small ones interposed. In 4 d, which is an enlargement of a portion of 4 c, two of the faces exhibit a single row of pores, but upon a third face there appear to be two series, one of which however is but imperfectly shown, as it is much obscured by the shading of the drawing. Specimens agreeing well with this figure, are common in the Devonian of Canada West. The other figures given by Goldfuss exhibit tubes one and a half lines in diameter on an average. He also states that one of his specimens came from Drummond Island. (Ferner kommt sie auch, nach einem Exemplar der Akademischen Sammlung auf Drummond-Island vor.) The specimen must have been therefore collected from the Niagara limestone, which we know to be the most recent rock of that locality.

2. EDWARDS and HAIME. Polypiers fossiles des Terrains Palæo. zoiques. p. 233.

These authors describe F. Gothlandica as consisting of convex somewhat elevated masses, with tubes a little unequal in size, each having ten or twelve radiating septa, represented by spiniform tubercles. On each face of the tubes two series of pores, each pore surrounded by a small elevated border; the pores of the same series a little more distant than is represented in the figures of Goldfuss.— They alternate a little with those of the neighboring series, and the spiniform tubercles representing the radiating septa more numerous and prominent than they are shewn to be by the same author. Diameter of the large tubes, three millemeters, or one line and a half.

In another work, BRITISH FOSSIL CORALS, Paleontographical Society's publications, Edwards and Haime describe the species in the same general terms, but state that the breadth of the calices is "somewhat more than one line." They consider F. Niagarensis, Hall, to be F. Gothlandica, and also deny that this latter species occurs in the Devonian.

3. PROF. McCoy, British Paleozoic Fossils, p. 20.

Pofessor McCoy thus describes F. Gothlandica," Corallum forming irregularly pyriform or very large circular, slightly convex masses, with concentrically wrinkled base, composed of polygonal tubes, averaging one line in diameter when adult, (but with occasional large irregular spaces, in which the diameter is only half a line,) with very numerous young smaller interpolated columns, of smaller diameter, and fewer angles; transverse diaphragms flat, about three in the space of one diameter; external walls as exposed in rough vertical fracture, slightly roughened by small transverse wrinkles, which obscurely crenulate the edges, sides with one or two rows of large round communicating pores.

"I agree with Mr. Lonsdale, in thinking that the Favosites absaltica, (Goldf. Sp.) characterised by having but one row of pores on each face of the tubes, should be viewed as only a variety of this species; as I think I have seen from one to three rows in portions of a single mass.

"Specimens from Gerolstein, in the Eifel, seemed to agree (on the most careful comparison of good specimens) perfectly with the silurian ones from Wenlock, and the carboniferous ones from Derbyshire. The great number of the young tubes gives a peculiar irregularity of aspect to the surface of this species."

It will be perceived by the above how widely the best paleontologists differ in their descriptions of F. Gothlandica upon the same very important point, the width of the corallites or tubes. According to Professor McCoy, they are upon the whole less than one line in diameter; the adult cells, or the largest, only reaching that size, while there are a great many much smaller. From Edwards and Haime we learn that they are over one line, while by the figures of Goldfuss they are shewn to be full one line and a half, the tubes above that size being more numerous than those below. This diversity might not appear to be of much consequence, and yet those geologists who have had occasion to work a good deal among rocks abounding with these corals know that the difference of half a line in the average size of the tubes in two specimens of Favosites gives to them a very dissimilar aspect, and strongly suggests the idea of two species. The more, however, we examine into the subject the more evident does it become that mere difference in size is not sufficient to separate species unless the internal structure also differs. At all events the above comparison

demonstrates to us the very weighty fact that in Europe F. Gothland ica is found to be variable in the character that is most generally relied upon as a means of identifying the species.

In order to ascertain whether or not our Canadian forms could be divided into several species, I undertook to write out a detailed description of each specimen in the large collection of the Geological Survey, noting the following characteristics:-1st, the diameter of the tubes. 2nd, the form of the diaphragm, and their structure, whether complete or incomplete. 3rd, the presence or absence of the spiniform tubercles. 4th, the number of rows of pores. 5th, the distance of the pores from each other. 6th, the presence or absence of the elevated border around the pores. 7th, the presence or absence of longitudinal lines or striæ on the faces of the tubes. The specimens were from Anticosti, Cape Gaspé, the coast of the Bay of Chaleurs, the Eastern Townships, the head of Lake Temiscamangue, the Niagara ridge, Drummond Island, and various localities of Devonian rocks in Canada West. It would be too much to give even a small portion of the details in this paper, and I shall therefore state briefly the principal results.

1st. The size of the tubes in all those specimens which have the internal characters of F. Gothlandica is variable, and ranges from three fourths of a line to a little more than two lines.

2nd. The greater number have the tubes between one line and one line and a half in width.

3rd. There are more specimens above one line and a half in the Devonian than in the Silurian.

4th. The diaphragms may be complete or incomplete in the same specimen, or in different parts of the same tube. This character is more common in Devonian than in Silurian specimens, and more so in the lower than the upper Silurian.

5th. The spiniform rays exist in both upper Silurian and Devonian specimens, but have not been observed in the lower Silurian.

6th. The pores are usually in two series, but specimens with one, two, or three rows, are not uncommon in both the upper Silurian and Devonian rocks. I have seen no pores in the lower Silurian specimens.

7th. The elevated border around the pores occurs in both Silurian and Devonian forms, and in the same specimen may be absent from one part and present in another.

8th. The pores are usually distant half a line from each other, but sometimes either less or more than that distance.

9th. The longitudinal lines on the faces of the tube may be either present or absent, in different parts of the same specimen, and it is in general much more strongly developed in the Devonian than in the Silurian rocks. I have seen it on European specimens.

If the observer, while examining any large collection of specimens from the upper Silurian or Devonian rocks of Canada, keep in mind and direct his attention to the investigation of the above characters, he will find innumerable shades of difference which will soon convince him that if they are to be regarded as of specific value, it would require nearly fifty specific definitions to give them all expression. It is scarcely necessary to state that a division to one-fourth of that extent would be absurd, and injurious to science. The species which I believe to have been too unguardedly set apart from F. Gothlandica are F. Goldfussi, F. Troosti, F. Niagarensis, Astrocerium parasiticum, and A. pyriforme.

The first of these, F. Goldfussi, (Edwards and Haime), was supposed to be different from F. Gothlandica, because although there were in general two rows of pores, yet some of the sides of the tubes exhibit one, and others three rows, and further that the pores are nearer together than in the typical species. I am perfectly satisfied that neither of these characters are sufficient.

F. Troosti, (Edwards and Haime.) Founded on the presence of the longitudinal lines on the faces of the tubes, is also not distinct, as that character occurs throughout the series.

F. Niagarensis, (Hall,) is thus described :-"Spheroidal or irregular in form, rapidly increasing by interstitial cells; walls of cells usually thin, pierced by two rows of minute pores; transverse septa thin, often oblique, or bent downwards." Professor Hall further states that it "differs from the F. Gothlandica in forming more usually small spheroidal masses, and in the rapid increase of cells almost entirely by interstitial growths, the base continuing small. The size of the cells is always less than in that species, and from this character alone it may be distinguished."

I think that this species consists of young pyriform or spheroidical colonies of F. Gothlandica or F. basaltica, and also that the other two A. parasiticum and A. pyriforme are the same. Wherever F. Gothlandica and F. basaltica occur, these small specimens are more or less common.