164 THE CANADIAN NATURALIST. [Vol. viii. 



tion, and that the layers crowded with Lingulce are thin, none 

 of them exceeding two inches in thickness ; but he thinks that 

 the dark colour of some of the associated sandstones and shales 

 is due to comminuted Linguloe. 



At Kamouraska, where I have studied these deposits, the 

 ordinary phosphatic nodules are of a black colour, appearing 

 brown with blue spots when examined in thin slices with trans- 

 mitted light. They are of rounded forms, having a glazed but 

 somewhat pitted surface — and are very hard and compact, 

 breaking with glistening surfaces. They occur in thin bands of 

 compact or brecciated limestone, which are very sparingly fossil- 

 iferous, holding only a few shells of Hyolithes and certain Sco- 

 lithus-\ike cylindrical markings. In some of these beds siliceous 

 pebbles occur with the nodules, rendering it possible that the 

 latter may have been derived from the disintegration of older 

 beds ; but their forms show that they are not themselves pebbles. 

 Phosphatic nodules also occur sparingly in the thick beds of 

 limestone conglomerate which are characteristic of this forma- 

 tion ; they are found both in the included fragments of limestone 

 and in the paste. The conglomerates contain large slabs and 

 boulders of limestone rich iu Trilohites and Hyolithes ; but in 

 these T have not observed phosphatic nodules. 



In some of the limestones the phosphatic bodies present a very 

 different appearance, first noticed by Richardson at Riviere 

 Ouelle, and of which I have found numerous examples at Kamou- 

 raska. A specimen now before me is a portion of a band of 

 grey limestone, about four inches in thickness, and imbedded in 

 dark red or purple shale. It is filled with irregular, black, 

 thick-walled cylindrical tubes, and fragments of such tubes, along 

 with phosphatic nodules — the whole crushed together confusedly, 

 and constituting half of the mass of the rock. The tubes are of 

 various diameters, from a quarter of an inch downward ; and the 

 colour and texture of their walls are similar to those of the ordi- 

 nary phosphatic nodules. 



Under the microscope the nodules and the walls of the tubes 

 show no organic structure or lamination, but appear to consist of 

 a finely granular paste holding a few grains of sand, a few small 

 fragments of shells without apparent structure, and some small 

 spicular bodies or minute setae. The general colour by trans 

 mitted light is brown ; but irregular spots show a bright blue 

 colour, due probably to the presence of phosphate of iron (vivi- 



