. The Quarterly journal of the Geological Society of London. eof teeth and the thinness of the shell, as well as the straisrhtnessof the hinge-line, remove our species from Astarte ; while themanner of occurrence prevents its inclusion among the borers. Abundant in a saudv micaceous bed, near the maximum ofAttenia eontorta. 204 PKOE. REYNOLDS AND MR. VAFGHAN ON THE [May I9O4. MODIOLA MINIMA, Sow. Our specimens agree well with Moores large figure (1), pi. xv,fig. 27. The anterior, upper slope (formed by the hinge-line) is somewhatshorter than the posterior, and rises at an angle of about 20° ;
. The Quarterly journal of the Geological Society of London. eof teeth and the thinness of the shell, as well as the straisrhtnessof the hinge-line, remove our species from Astarte ; while themanner of occurrence prevents its inclusion among the borers. Abundant in a saudv micaceous bed, near the maximum ofAttenia eontorta. 204 PKOE. REYNOLDS AND MR. VAFGHAN ON THE [May I9O4. MODIOLA MINIMA, Sow. Our specimens agree well with Moores large figure (1), pi. xv,fig. 27. The anterior, upper slope (formed by the hinge-line) is somewhatshorter than the posterior, and rises at an angle of about 20° ; theposterior slope is nearly straight : the angle between the twoslopes is about 145:. The greatest breadth occurs at the junctionof the two slopes, and is nearly half the largest dimension. Thelower border is nearly straight. The front end is pointed, but thereis no distinct separation of a lower, anterior, swollen portion. Specimens are not uncommon throughout the Rhaetic. Myophoria postera, Qu. (2). Especially common at the maximum of Avicula Caedinia concinna, Sow. aff. re- Fig. 4.—Diagram of Cardiniagularis, Terq. (PI. XVIII, concinna. Soiv. ((iff. C. regu- lig. 4, & text-fig. 4.) laris, Terq.). General contour uniformlyoval ; lower border broadly anduniformly convex ; hinge-linenearly straight, and only slightly /1^ \v^_converging. Curvature of an-terior and posterior bordersnearly equal. Beak not pro-minent : lunule small. Thegrowth-lines form strong con-centric bands. [Magnified 2 diameters.] Dimensions in millimetres. Spec. 1. Spec. 2. Horizontal 21 30 Vertical 13 16o Position of beak 5-16 7-23 Radius of curvature of anterior border 5 5 Radius of curvature of posterior border .> 45 As Brauns points out (5), p. 338, it is impossible to separate thespecies of Cardinia on slight changes of form, between which thereis every possible mutation. He has consequently limited the numberof Lower Jurassic species to three, namely : C. concinna, C. crassi-nscida, a
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectgeology, bookyear1845
