322 COLLYRITES. 



in thickness, and capping all the other deposits in a disorderly manner, without absolute 

 continuity. 2d, chalh. 3d, upper-green-sand — very thin, but full of fossils, and now 

 worked much for the phosphatic nodules called (by mistake) coprolites ; 3 a, gait 3 b, 

 lower-green-sand resting, with some discordance on the beds below. It is seen in one 

 place resting on good Kimmeridge clay, in another immediately on Oxford clay. 4th, 

 Kimmeridge clay. 5th, Coral rag, or Middle Oolite — no Portland Oolite in this country. 

 The Coral rag is not continuous, and is only well seen in one spot, but it may exist in other 

 places under the drift which conceals so many of our strata. 6th, Oxford clay. 



" The lower OoHtic terrace, including everything from Cornbrash to Inferior Oolite, is 

 far removed from us. 



" There are good brick-pits in the upper part of the Oxford clay, and immediately 

 over the clay are some stone bands, which may possibly represent the base of the Coral 

 rag. My belief is that your fossil {Colhjrites bicordata, Leske,) has been drifted out of 

 the Coral Rag or Middle Oolite, which will agree well with your idea of the true place of 

 this species." 



The foreign distribution of this fine species is, according to M. Desor, from the Terrain 

 a Chailles, or Inferior Corallian, equivalent to the lower calcareous grit of English geolo- 

 gists ; in the Swiss Jura, it is found in that stage at Fringeli, Liesberg, Wahlen, Delemont, 

 Porrentruy ; of the Salinois Jura, at Mont Bregille, near Besan^on. It is collected in the 

 same stage in France, according to M. Cotteau, from the " Calcaires Oxfordiens '' of Lucy- 

 le-Bois, Villiers-les-Hauts (Yonne). 



