20 R. ETHERIDGE, JUN., ON LOWER-CARBONIFEROUS 1NVERTEBRATA. ridges are plain and unornamented, and not in any way denticulated or notched. They unite subalternately with the median ridge, the point of junction being marked by a slight enlargement or button. The flattened interspaces between the transverse ridges are minutely wrinkled vertically. The explanation of this is probably that given by Mr. J. de C. Sowerby, who, in describing C. quadrisulcata says : — " Many of the specimens in ironstone have smooth furrows be- tween the crenated ridges ; in others the furrows are crossed by striae ; and both these forms may sometimes be found in one speci- men, and arise from the presence or absence of a thin dark brown skin or covering, the interior of which is smooth and the exterior wrinkled " *. Loc. and Horizon. Woodhall, as before. Class CEPHALOPODA. Genus Nautilus, Breynius. Nautilus cariniferus, J. de C. Sowerby?. PI. II. figs. 31, 32. Nautilus cariniferus, J. de C. Sow. (1824), Min. Con. v. p. 130, t. 482. figs. 3, 4; Phillips (1836), Geol. Yorksh. ii. p. 232, t. 17. fig. 19 ; De Koninck, Anim. Eoss. Terr. Carb. Belg. p. 549, t. 48. figs. 11, 12 ; Brown (1849), Foss. Conch, p. 32, t. 22. Obs. In the impression of the specimen represented by fig. 31, there are distinct traces of the denticulated keels of the above spe- cies, still more distinctly seen in the fragment, fig. 32. Were it not for the crenulated ridges or keels, marking a distinctive cha- racter, these fragments would scarcely be worth notice ; but the paucity of marine life, speaking generally, in the Lower Carbonife- rous rocks around Edinburgh, renders it necessary to catalogue every fragment exhibiting the slightest trace of definite characters. If the reference to N. cariniferus is correct, then Prof. De Koninck's suggestion that the shell was covered with fine transverse striae is confirmed. These may be seen on a part of the flattened impres- sion, as well as similar longitudinal lines. Loc. and Horizon. Woodhall, in the shale with other marine fos- sils, as before. Nautilus, sp. ind. Obs. A crushed and compressed example obtained by Mr. Gall at Craigleith, somewhat resembling in general appearance N. cyclosto- mus, Phil! , ; but, except for the fact that it proves the presence of a Nautilus in the band of shale at Craigleith, the specimen is quite useless for specific identification. Loc. and Horizon. Craigleith Quarry, in shale above the sandstone, Cement-stone group. Cabinet of Mr. Gall.
- Trans. Geol. Soc. 2nd ser. v. (expl. of pi. xl.).
