the length; sides gently concave in the posterior two-thirds, and slightly diverging from each other forwards; anterior third and front uniformly rounded. Neck segment with the margin convex and projecting backwards, an obscure tubercle, or rather, an angular elevation in the middle, neck furrows all across. There are four glabellar furrows; of these, the posterior is strongly marked and extends in a nearly straight line all across; the next two are linear, slightly impressed, extend inwards about one-third the width of the glabella and are gently curved backwards, but still almost at right angles to the sides. The anterior furrow is short, extends inwards about one-fifth the width of the glabella, and curves backwards at an angle of about 45° to the sides. The dorsal furrow around the glabella is very shallow. The fixed cheeks are triangular, nearly flat, with a small elevation, close to the extremity of the posterior furrow. Front of the head with a moderately convex marginal rim, almost in contact with the glabella or separated therefrom by a narrow space. The eye-lobe starts from a point close to the side of the glabella and just opposite or a little behind the short frontal furrow, and runs with a gently sigmoid curve (at first convex outwardly, and then concave) backwards and outwards to the posterior marginal furrow, which it reaches at a distance from the sides of the glabella, about equal to the length of the neck segment. The facial suture leaves the side of the glabella a little in front of the anterior furrow, and runs outwards, nearly at a right angle, but with a gentle convex curve, to the margin.

The surface is covered with fine rippled striæ. These on the marginal rim are irregularly parallel with the margin; on the glabella they curve around the front, but further back, and on the neck segment they have a rudely longitudinal direction, curving outwards in crossing over the glabellar lobes.

Length of the head of the largest specimen examined, 6 lines; length of the glabella, including neck segment, 5 lines; width of glabella at the neck segment, 3 lines, at the front pair of furrows, 3 iines; width of the posterior margin of the fixed cheek 3 lines; length of the eye lobe, 4 lines.

When compared with the species figured by Salter and Hicks the following differences become apparent:-A. Henrici, Salter, has the eye lobes with a gently uniform curve outwards. In A. Salteri, Hicks, the eye lobes are also convex and the glabella proportionally longer, while the neck furrow "is the only one

continued across." (Hicks.) A. impar, Hicks, has the flexuous eye lobes of our species, but the marginal rim is more decidedly in contact with the front of the glabella, while the two median pairs of furrows extend further inwards.

Occurs at Chapel Arm, Trinity Bay.

PARADOXIDES TENELLUS, spec. nov.

Fig. 12.

Neck segsituated a

Description.-Glabella clavate, convex, most elevated at the anterior third of the length, front and sides in the anterior half, rounded, becoming sub-parallel in the posterior half. ment strongly elevated in the middle, where there is small tubercle, neck furrow extending all across. There are four glabellar furrows, of which the posterior extends across but is very indistinctly impressed in the middle; the next two in advance extend inwards about one-third of the width of the glabella, while the small one in front is somewhat shorter. The furrows are all nearly at a right angle to the longitudinal axis, and about equidistant from each other. The anterior margin of the head, is bordered by a narrow convex rim, which is separated from the front of the glabella by a flat space, varying in width from once to thrice its (the rim's) width. The fixed cheeks are subtriangular and nearly flat. The anterior extremity of the eye lobe is situated at a point nearly opposite, but a little behind, the anterior furrows, and is close to, but not in contact with the side of the glabella. The lobe is slightly sigmoid, its posterior extremity opposite the last glabella furrow. The dorsal furrow is distinctly impressed along the posterior half of the glabella but obscurely marked in front.

The surface is minutely granular. In all of the three specimens collected there is a small straight rounded ridge, which runs from the front of the glabella to the margin. It is situated exactly on the median line.

Of this species we have three specimens of the glabella, two of which retain portion of the fixed cheeks and show the form of the eye. The largest is three lines in length, including neck segment and front margin.

Occurs at Chapel Arm, Trinity Bay.

PARADOXIDES DECORUS, spec. nov.

Description. The form of the glabella of this species is nearly the same as that of P. tenellus but the glabellar furrows are

somewhat different. The posterior pair seem to be entirely disconnected in the middle and the next two pairs are rather more curved. The marginal rim of the front of the head, seems to be close up to, and in contact with, the front of the glabella. The surface is ornamented with minutely corrugated, raised lines which, in some places, anastomose so as to present an irregularly reticulated appearance. This at once separates the species from P. tenellus, the surface of which is minutely granulated. The surface of A. venustus is somewhat like that of this species, but the raised lines are more distant, and besides the posterior glabellar furrow extends all across. The length of the most perfect glabella examined is about thirteen lines. Only three fragments, (all of the glabella) of this species occur in the collection. Form of the eyes and of all other parts unknown. It occurs at Chapel Arm, Trinity Bay.

Genus IPHIDEA, gen. nov.

13

FIG. 13. Iphidea bella; ventral? aspect.

Of this genus we have no specimens showing the internal structure, but the external characters seem sufficient to separate it from any described generic group. The ventral? valve of I. bella, is conical, strongly elevated at the beak, hinge-line nearly straight, posterior angles narrowly rounded, sides and front nearly uniformly rounded, forming rather more than a semi-circle. Posterior side with a large false area, and a convex pseudo-deltidium, the width of which at the hinge line is nearly one-third the whole width of the shell. The dorsal valve is semi-circular, moderately convex most elevated at the beak. The hinge-line appears to be straight. The form and structure of the posterior side, (such as the area, foramen, deltidium, &c.,) cannot be made out from the specimen, owing to its imperfection. The surface is covered with fine concentric striæ, which in the ventral? valve are continued around on the area. Of these striæ there appear to be from 15 to 20 in the width of one line, their size varying somewhat in different parts of the specimen. There are also a few obscure radiating striæ. Width of ventral valve, 7 lines; length, 5 lines; height, 2 lines.

In the specimen above figured there is an aperture in the beak, but in another there is no appearance whatever of a perforation. This genus resembles Acrotreta, but differs therefrom in having a large convex deltidium. It seems to be also closely allied to Kutorgina. The shell which I have described under the name of Obolus Labradoricus belongs to this genus.

I. bella was found by T. G. Weston, in a boulder of limestone associated with numerous fragmentary trilobites, of primordial age, near Trois Pistoles below Quebec. A closely allied species of the same genus occurs in the primordial limestone at Topsail Head, Conception Bay, Newfoundland.

FOSSILS IN THE HURONIAN ROCKS.

ASPIDELLA TERRANOVICA, nov. gen. and spec.

FIG 14. Aspidella terranovica, two specimens on a small slab of stone, slightly restored.

These are small ovate fossils five or six lines in length and about one-fourth less in width. They have a narrow ring-like border, within which there is a concave space all round. In the middle there is a longitudinal roof-like ridge, from which radiate a number of grooves to the border. The general aspect is that of a small Chiton or Patella, flattered by pressure. It is not probable, however, that they are allied to either of these genera.

Associated with these are numerous specimens of what appear to be Arenicolites spiralis, a fossil that occurs in a formation lying below the primordial rocks in Sweden. These fossils were first discovered by A. Murray, Esq., F.G.S., in 1866. Other specimens were collected by Capt. Kerr, R.N., Mr. Howley and Mr. Robertson.

They occur near St. Johns, in the Huronian. A more detailed description will be given hereafter.

STENOTHECA PAUPER, spec. nov.

Description.-Shell small, conical, with the apex incurved, laterally compressed. Aperture ovate, elongated in the plane in which the curvature of the apex occurs. Surface with four or five small engirdling convex ridges. Length of aperture about 1 lines; width about 1 line; height of shell about 1 line. Occurs in the red limestone at Bridgus, Conception Bay. In the Quar. Jour. Geol. Soc. of May last, Mr. Hicks has described and figured, under the name of Stenotheca cornucopia, a small shell which is evidently congeneric with this. To the same genus should perhaps be referred the shell known as Metoptoma rugosa of the Lower Potsdam ? of New York.

SCENELLA RETICULATA, gen. and spec. nov.

Description.-Shell small, almost uniformly depressed, conical; apex central or nearly so; an obscure carina extending from the apex down one side to the margin. Aperture nearly circular, apex very slightly incurved towards the side opposite the carina. Surface reticulated with fine radiating and engirdling striæ, just visible to the naked eye. Diameter of the aperture of the largest specimen collected, 3 lines; height of the apex, 2 lines.

Occurs at Topsail Head, Conception Bay.

Species resembling this have been heretofore referred to Capulus, Metoptoma, &c., to which, however, they do not belong. For the present I propose to refer those with a strongly corrugated surface to Stenotheca, and the others with a smoother surface to Scenella.

(To be Continued.)

WHAT IS TRUE TACONIC ?

BY PROF. JAMES D. DANA.

The true use of the term Taconic should be learned from Prof. Emmons's first application of it when he made his formal announcement of the "Taconic system." In his final New York Geological Report, 4to., 1842, the rocks so-called are those of the Taconic mountains, on the borders of Massachusetts and New York, together with the quartzite, limestone, and slates adjoining on the east, and not the slates far west of these mountains; †

* Professor Emmons opens the subject of the "Taconic System in his final Report (1842) by saying that it extends north through Vermont to Quebec, and south into Connecticut; but the only rocks he describes as the rocks of the system are those of Berkshire County,