338 On the Chemical Composition of Recent and Fossil Lingulse. 



cylindrical in shape, and from one-eighth of an inch to an inch 

 in diameter; they sometimes make up the larger part of the 

 conglomerate. Iron pyrites in small globular masses occurs 

 abundantly with them, often filling their interstices, but is not 

 found elsewhere in the rock. These coprolites are finer grained 

 and more compact than those from the Ottawa, and have a con- 

 choidal fracture ; their colour is bluish or brownish-black ; the 

 powder is ash-gray, becoming reddish after ignition. They have 

 the hardness of calcite, and a density of 3-15. When heated 

 they evolve ammonia with an animal odour, and with sulphuric 

 acid give the reactions of fluorine. The quantitative analysis of 

 one gave — 



Phosphate of lime, PO^ 3CaO* . . 40-34 per cent. 

 Carbonate of lime, with fluoride . . 5"14 

 Carbonate of magnesia .... 9*70 

 Peroxide of iron with a little alumina 12'62 



Oxide of manganese trace 



Insoluble siliceous residue . . . 25*44 

 Volatile matter 2* 13 



95-37 

 The iron exists, in part at least, as carbonate, and its introduc- 

 tion in so large a quantity, giving colour and density to the 

 coprolites, is doubtless connected with the formation of iron 

 pyrites by the deoxidizing action of organic matters. The 

 production of an equivalent of bisulphuret of iron from a neutral 

 protosulphate of iron, which alone could exist in contact with 

 limestone, must be attended with the elimination of an equivalent 

 of protoxide of iron, for 2(S03 . FeO) -0^ = Fe S^ + FeO. 



It is remarkable that no traces of Lingul(e or any other shells 

 have been detected with these coprolites. Thin sections of 

 them are translucent, and under the microscope are seen to con- 

 sist of a fine granular base, in which are imbedded numerous 

 grains of quartz, and small siliceous spicul?e, like those of some 

 sponges. In a bed of sandstone, associated with these conglo- 

 merates and slates at Riviere Ouelle, were found several hollow 

 cylindrical bodies, resembling bones in appearance. The longest 

 one is an- inch and a half long, and one-foui-th of an inch in dia- 

 meter. It is hollow throughout, and had been entirely filled 

 with the calcareous sandstone, in which it is imbedded, and 

 whose disintegration has left the larger end exposed. The 

 smaller extremity is cylindrical and thin, but it gradually en- 

 larges from a thickening of the walls, and at the other end 

 becomes externally somewhat triangulariform ; the cavity remains 

 nearly cylindrical, but the exposed surfaces are rough and irre- 

 Kular within. 



