234 
THE GEOLOGIST. 
XLVIII. — LiNGULA MYTiLOiDEs. Sowerby. PI. v., figs. 3843. 
Lingida mi/tiloides. Sowerby, "Min. Con.," tab. xix., fig. 1-2, 1813, = Liii- 
ijiila ellipiica and = L. parallela, Phillips' " Geology of Yorksliii-e," vol. ii., 
■plate xi., figs. 11-15 and 17-19, 1836. 
This shell appears to vary in shape, but is usually more or less regularly 
elliptical or ovate, with its greatest width cither towards tiie posterior or an- 
terior extremity. Its sides are also sometimes nearly parallel and rounded in 
front, but both front and beaks are in other examples about equally and regu- 
larly elliptically attenuated. The valves are generally convex, and most 
elevated along the middle, where there exists likewise a flatness, which becomes 
gradually wider as it extends from the apex of the beak to the front, the lateral 
portions of the valves sloping rather abruptly ou either side, while the surface 
is marked at intervals by a greater or smaller number of concentric lines or 
ridges of growth. The shell under description has been referred to Sowerby's 
L. mytiloiclcs, because several of the specimens were exactly similar in shape to 
those figured by Sowerby, in 1813, and from it having appeared that L. paral- 
lela and L. elliptir.a were only slight variations in shape of the Sowerby shell (?). 
Some palaiontologists will however, differ with me in this conclusion, and may 
prefer retaining L. mytiloidcs and L. parallela as separate species, and I should 
DC glad to adopt their views if they can point out the characters by M'hich the 
two can be distinguished.* L. mytiloidcs has usually a glossy appeai-ance, and 
was probably when alive of a bright green colour ; it is also a common Scottish 
species. 
In the parish of Carluke, in Lanarkshire, it occurs in the slaty ii-onstone, at one 
hundred and sixty fathoms below the "Ell coal;" two hundi-edand thirty -nine 
at Gare ; three hundred at Mashock Burn ; three hundred and thirty-seven at 
Raes GiU, Braidwood, and Langshaw Burn, etc. ; three hundred and seventy- 
one at Kilcadzow. It occurs likewise at Hall Hill, near Lesmahago ; Capel 
Rig, East Kilbride; Calderside and Auchentibber, High Blantyre; Bishop- 
briggs and Bobroyston, north of Glasgow. In Renfrewshire, at Orchard- 
quarry, Thornliebank. In Ayi'shu-e, at West Broadstone, Beith. In Stirling- 
shire, at Craigenglen, and Corrie Biun. In Eifesliire, at Craig Hartle, etc. It 
has also been found along the Bcrwickshu-e coast : and at Marshall Meadows, 
three miles north of Berwick, a very elongated variety has been discovered by 
Mr. Tate, and for which he proposes the designation of L. elongata. 
XLIX. — Spirifeeina laminosa. M'Coy. PI. v., figs. 8-9. 
Cyrlla laminosa. M'Coy, " Synopsis of the Carb. Fossils of Ireland, p. 137, 
pi. xxi., fig. 4, 184i. Spirifera id., " Dav. Br. Carb. Men., pi. vii., figs. 17-22. 
This form is generally sub-rhomboidal, with convex valves, the lateral por- 
tions of the shell being regularly cuiwed, with acute cardinal extremities : the 
hinge-line is as long as the greatest width of the shell. The area large, tri- 
angular, and divided by a fissure of moderate width. The beak is small, and 
not much produced above or beyond the level of tlie area. The mesial fold in 
t he dorsal valve is broad, more or less elevated, and without ribs, whOe the 
sinus in the ventral valve is wide, and of moderate depth ; there exists also on 
the lateral portions of each valve from sixteen to twenty narrow radiating ribs, 
intersected by closely disposed, sharp, concentric, undulating laminae. 
This species evidently exists in Scotland, although no perfect example with 
* At page 36S of his History of British Animals," whilo describing Lin/jula mytUoides, Dr. 
Fleming refers to Ure's plate xvi., fig. 5, ss probably belonging to the species in question, but 
1 am convinced that this is a mistake, as the shell there represented is fai' from resembling 
any Lingula with which I am acquainted. 
