. Geological magazine. xcentric position of something which mayhave been the siphuncle. There is also a depression at the anteriorend, but this seems to be the impression of another organism. Thesurface of the cast is smooth; there are no traces of any specimen, characterized by its deep chambers and slowlytapering shell, appears to be related to the Devonian form whichKayser has figured (loc. cit., pi. x, figs. 1-3; pi. xi, figs. 4, 8) asOrthoceras commutatum, Giebel, and recorded from the limestone at This is the species which was described as Orthoceras longicameratum by Foor
. Geological magazine. xcentric position of something which mayhave been the siphuncle. There is also a depression at the anteriorend, but this seems to be the impression of another organism. Thesurface of the cast is smooth; there are no traces of any specimen, characterized by its deep chambers and slowlytapering shell, appears to be related to the Devonian form whichKayser has figured (loc. cit., pi. x, figs. 1-3; pi. xi, figs. 4, 8) asOrthoceras commutatum, Giebel, and recorded from the limestone at This is the species which was described as Orthoceras longicameratum by Foord(Cat. Foss. Ceph. Brit. Mus., pt. i, 1888, p. 80), but this name being preoccupiedFoord altered it to 0. nassoviense (ibid., Corrigenda and Addenda, p. xxxi). Thespecies, however, is evidently the same as that for which Giebel had already proposedthe name 0. commutation. 156 G. C. Crick—Fos-iil Cephalopoda Hasselfelde in the Hartz, a locality which also yields the previously-mentioned species, Orthoceras Fig. 1.—Orthoceras cf. commutatum, C. G. Giebel, sliowing mternal casts of threechambers, and of part of a fourth. \a, anterior end of the same Hill, St. Miuver, Cornwall. Drawn of two-thirds of the natural size.(The reduction of the ligure causes the chambers to appear shallower than theyreally are.) COPHINOCERAS Sp. (PI. V, FigS. 8rt, 86.) The fossil which is here referred to this genus consists of a naturalinternal cast of a (probably the greater) part of the body-chamberand of the six preceding chambers of a slightly curved shell. Itineasures on the outer or convex curve about 140 mm., of which thebody-chamber occupies about 82 mm. Only one side and a smallportion of the other are exposed. The specimen is much flattened,its greatest thickness being only about 28 mm. The greatest width ofthe fossil is at about the middle of the portion of its septate part, andis about 78 mm., but the boundary of tlie concave surface of thespecimen is not expos
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1864
