. The geology of Nova Scotia, New Brunswick, and Prince Edward Island, or, Acadian geology [microform]. Geology; Geology, Stratigraphic; Paleontology; Geology, Economic; Géologie; Géologie stratigraphique; Paléontologie; Géologie économique. 1 I '1 FOSSILS. 609 sp ine. ly semi- surface josterior. directly ; is dextral, tran8verE<j to the dorsftl margin and a little nearer the anterior side. The antenor ridge consists of a single highly elevated, rounded or papillose tubercle near the dorsal margin, atid an elongated elliptical tubercle placed obliquely near the antcro-vcntral margi
. The geology of Nova Scotia, New Brunswick, and Prince Edward Island, or, Acadian geology [microform]. Geology; Geology, Stratigraphic; Paleontology; Geology, Economic; Géologie; Géologie stratigraphique; Paléontologie; Géologie économique. 1 I '1 FOSSILS. 609 sp ine. ly semi- surface josterior. directly ; is dextral, tran8verE<j to the dorsftl margin and a little nearer the anterior side. The antenor ridge consists of a single highly elevated, rounded or papillose tubercle near the dorsal margin, atid an elongated elliptical tubercle placed obliquely near the antcro-vcntral margin, and in older specimens sometimes swelling and spreading over the margin. The posterior ridge rises near the dorsal margin, and making a slightly broader curve than the posterior end of the valve approaches the ventral margin at the centre: the ridge is high and angular with a small prominent tubercle at the dorsal extremity, and from four to six smaller spine-like tubercles along its curve. The central ridge or tuber- cle is separated from the lateral ridge by a distinct furrow, and its con- tinuation from the base of the tubercle passes between the lower ends of the two lateral ridges. Ventral and lateral margins with a narrow thickened rim. This species resembles very nearly the B. tuberculala of Klodeii, as described and figured by Mr T. Rupert Jones. In our specimens the dorsal angles are more rounded; the posterior ridge at its base is never extended beyond the middle of the valve, and is marked on its crest by several small spine-like tubercles. The anterior ridge is usually more extended along the ventral margin in our specimens, and the furrow is better defined, while the tubercles are never flattened above or overhanging the base as shown in the European specimens. Smaller specimens, which appear to be the young of this species, pre- sent some slight variations of surface markings, but show less difference than the young of B. tuberculata. Arisaig, coll. J. W.
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Keywords: ., boo, bookcentury1800, booksubjectgeology, booksubjectpaleontology
