. Report upon the palaeontology of the province of Ontario [microform]. Paleontology; Paléontologie. a d Fm. 27. Corniferous Limestone, and present a very characteristic appearance. The umbonal region of the cast exhibits the filling:; up of the rostral cavity, in the furra of a sub cylindrical or tongue- shaped projection, which is usually grooved on its upper surface, and which is biundcd later- ally by the deep fissures left by the dental lamelhe. In front the cast of the rostral cavity passes into a great hump or abrupt prominence formed by the cast of the muscular impression. The umbonal
. Report upon the palaeontology of the province of Ontario [microform]. Paleontology; Paléontologie. a d Fm. 27. Corniferous Limestone, and present a very characteristic appearance. The umbonal region of the cast exhibits the filling:; up of the rostral cavity, in the furra of a sub cylindrical or tongue- shaped projection, which is usually grooved on its upper surface, and which is biundcd later- ally by the deep fissures left by the dental lamelhe. In front the cast of the rostral cavity passes into a great hump or abrupt prominence formed by the cast of the muscular impression. The umbonal slope of this prominence is smooth, and has a median ridge running into the rostral cast; and the front slope is conspicuously striated with longitudinal striae, and often divided into two halves by a mesial ridge. " The interior of the dorsal valve shows a strong cardinal process, with a shallow spoon-shaped depression in the centre, mar- gined by deep teeth sockets. The muscular area is elongate-ovate, broader above, and divided through the centre by a thin ele- vated septum. . The crura appar- ently bend downwards from near their origin; thence recurving, they follow very closely the contour of the dorsal valve, making thirteen or more turns in an indivi- dual of medium size. Spires, slender and a. Cast of the interior of the ventral viilvo of AilwfHH nmnitn, • 1 " /m n p / A' V /< V 1 TV (Conrad), from the Corniferous ;(<iri!{inal); i, Interior of "'"IP'G (riaU, 1 lU. i\eiO I01K, VOL, IV., the ventral valve of tile saiiio (after Hillings). p_ 301). Lomlitji and Formation.—Common in the Corniferous Limestone of Port Colbornc and Hagersville. 106. Atiiyri8(?) Maia (Billings). A/hijris Maia (Billings), Canadian Journal, New Series, Vol. V., p. 270, Figs. 33, 34. (?)Spirifera Maia (Hall), Pal. New York, Vol. IV., Plate XLTIL, Figs. (5-13. Shell broadly ovate, or sub-rhomboidal; valves convex, the ventral valve most so. Ventral valve stron
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectpaleontology, bookyea
