Fossils of the Chazy Limestone, 429 



pora and in some of the specimens I think I can see some traces 

 of connecting processes between the tubes, but the indications 

 are not sufficiently distinct to be relied upon. The tubes are 

 usually filled with white calcareous epar. 



I strongly suspect that the tubes were during the period of 

 their vitality filled with a delicate vesicular tissue similar to that 

 of a Syringopora or Cystiphyllum, and should this structure be 

 hereafter detected, the species must be either referred to Syring- 

 opora or a new genus must be formed for its reception. On the 

 other hand, both transverse diaphragms and radiating septa may 

 be discovered, in which case it must remain in the genus 

 Columnaria. 



Locality and formation. — Mingan Islands, Island of Montreal, 

 and near the city of Ottawa. Chazy limestone. 



Collectors. — Sir W. E. Logan, J. Richardson, and E. Billings. 



Figs. 3, 4, 5, 6. 



Figs. 3, 4, 5, 6. — Bolbopo^ites Americanus. Fig. 3 represents the 

 small pit in the base. 



BOLBOPORITES AMERICANUS. (N.S.) 



Description. — These curious little fossils consist of a smooth 

 solid hemispherical base surmounted by a conical projection 

 which is celluliferous, the cells being about the size and shape of 

 those of the common Stcnopora fibrosa. In the centre of the 

 base there is a small pit which appears to have been the point of 

 attachment. The solid part, under the hammer, usually breaks up 

 into rhomboidal fragments, but some specimens when fractured 

 exhibit a prismatic structure, the prisms radiating from the centre 

 and beino; about the size of the tubes in the celluliferous conical ex- 

 tremity. It is remarkable that the cells slope downwards instead 

 of upwards as in all other zoophytes, and it is possible that the 

 apex of the cone is the base : the greater size and the solidity of 

 hemispheric extremity, however, would seem to favour the oppo- 

 site conclusion. 



The specimens are from three to eight lines in length, and 

 about the same in greatest diameter. The cone is usually of the 

 same height as the hemisphere, but sometimes it is either shorter 

 or longer. 



