. Acadian geology : the geological structure, organic remains, and mineral resources of Nova Scotia, New Brunswick, and Prince Edward Island. Geology -- New Brunswick; Geology -- Nova Scotia; Geology -- Prince Edward Island; Paleontology -- New Brunswick; Paleontology -- Nova Scotia; Paleontology -- Prince Edward Island. 596 THE UPPER SILURIAN. ventral valve variably convex, and often showing a flattened or slightly concave space down the middle of the shell; cardinal margin ornamented by four or five minute spines on each side of the beak; cardino-lateral margins often a little wrinkled; surf
. Acadian geology : the geological structure, organic remains, and mineral resources of Nova Scotia, New Brunswick, and Prince Edward Island. Geology -- New Brunswick; Geology -- Nova Scotia; Geology -- Prince Edward Island; Paleontology -- New Brunswick; Paleontology -- Nova Scotia; Paleontology -- Prince Edward Island. 596 THE UPPER SILURIAN. ventral valve variably convex, and often showing a flattened or slightly concave space down the middle of the shell; cardinal margin ornamented by four or five minute spines on each side of the beak; cardino-lateral margins often a little wrinkled; surface finely striated, strise flexuous, dichotomising and increasing by interstitial addition, so that there are more than 100 on the margin of the shell; striae increasing in size below the umbo; concentric stride fine, close, rounded and slightly undulating. Fig. 198. Crania Acadieiisis. Fig. 199. Clwnetes Nova Scotica, and portions magnified. Fig. 201. Trematospira Fig. 200. CJumetes tenuistriata. Fig. 202. Leptocoelia intermedia. Dorsal valve moderately concave; stride much stronger below the middle of the shell and sometimes bifurcating toward the margin. This species resembles in form the Chonetes cornuta of the Clinton group of NeAV York, but is a much larger and more ventricose shell; the strife are proportionally less numerous and more closely aiTanged, the interstices being less than the strife, while in the C. cornuta the interstices are wider than the stride, and the latter increase only by interstitial additions below the middle of the shell. A stronger and more elevated stria often marks the median line from beak to base of the ventral valve. Arisaig, East River, Nictaux, coll. J. W. D. Chonetes tenuistriata., Hall (Fig. 200). Shell semi-oval, twice as wide as long; ventral valve moderately convex, hinge-line equalling the v/idth of the shell; surface marked by fine, even, closely arranged strige, which apparently increase only by interstitial additions, a
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Keywords: ., bookauthordawsonjohnwilliamsir1, bookcentury1800, bookdecade1870
