ARTICLE XUll.—Fossils of the Hamilton Gmup^ 



The following description of the fossils represented on the plate,. 

 and by the accompanying wood cuts are from the geology of New 

 York, by Professor Hall. Many of them wnlt be found in the- 

 western part of Upper Canada, where the Hamilton group occurs. 

 Fig. 1. Cucullea opima. "Ovate, very convex ; beaks near the 

 anterior extremity, very prominent; surface marked by strong 

 concentric lines ; cast nearly smooth ; impression of the internal 

 laminae, oblique. When compressed this fossil has the appearance 

 of a Nucula^ but the impressions of the internal laminae seem- 

 sufficient to warrant its reference to Cucullea^'' 



The generic name is from the Latin, Cucullus, ^hoodi ; the name 

 is probably from opimus^ fat, or well grown. 



Fig 2. Nucula ohlonga. " Oblong, elliptical, very inequilateral, 

 very finely and concentrically striated ; an impressed line extends 

 from the hinge, just forward of the beak, halfway to the base." 



Generic name from the Latin, Nucula a little nut ; OhlonguSy 

 obi on o-. , '' • 



Fig. 3. Nucula lineata, " Sub-triangular, convex ; beak much 

 elevated ; surface covered with coarse concentric striae." 

 Lineata, covered with lines or strise. 



Fig 4. Ci/pricaixlia truncaia (Conrad.) "Trapezoidal, surface 

 covered with concentric wrinkles ; posterior slope sharply carinated. 

 The wrinkles on the posterior slope are parallel to the truncated 

 margin and nearly at right angles with those upon 'the side of 

 the shell." 



The generic name is from the Greek, Kujyrinos^ related to the 

 goddess Venus, and ICardia, the heart; truncata, \aiin, truncated 

 or abruptly cut otl. 



Fig. 5. Tellina ovata. " Generiil form ovate, produced posteriorly 

 and apparently slightly gaping at the extremity ; posterior slope 

 angulated ; surface covered by minute concentric striae, which 

 become more prominent near the margin." 



Generic name from the Greek, telline, a sort of mussel, ovata^ 

 oval or eggshaped. 



Fig 6, Nucula hellatula. " Ovate, somewhat contracted neap 

 the posterior extremity ; surface covered with regular, fine con- 

 centric strise ; teeth in the hinge margin very distinct ; there is a 



