608 SIR J. W. DAWSON ON BURROWS AND TRACKS OP 



The wall of the tube is somewhat thick and composed of fragmental 

 matter, cemented by a dark-coloured organic substance. It is to 

 be observed that in the case of tubes, as distinguished from mere 

 burrows, like ScoUthus, when two or more are attached together an 

 appearance of branching results. 



Tubes apparently of similar character, but of considerably larger 

 size, occur in the same formation ; and many obscure cylindrical or 

 flattened bodies, not distinguished from branches of Algae, may be 

 of the same nature. I would also refer to a similar origin, and 

 provisionally to this genus, the curious primordial burrows from the 

 Hastings group described in the Quarterly Journal of this Society * 

 in 1866, and the phosphatic tubes from the limestone of the Quebec 

 group at Kamouraska, described in the Quart. Journ. Geol. Soc. in 

 1876t. The latter, however, I fancy are composed of excremen- 

 titious matter, or debris of the food of worms feeding on Lingu- 

 loid shell-fish. 



While preparing this paper, T have re-examined these tubes, and 

 have had some new slices prepared. These confirm my previous 

 statements. The thick walls of the tubes are destitute of lamination, 

 and have a finely granular texture, resembling that of the paste of 

 coprolites. They contain a few fine grains of sand, and minute 

 fragments of shells and of carbonaceous fibres. The whole seems to 

 indicate that they are formed, as already stated, of the phosphatic 

 dejections of animals subsisting on Lingulce, Trilohites, Hyolithes, 

 and other creatures having coverings of calcium-phosphate. 



In the same paper I referred to the fact that the shells of Hyo- 

 litliesX [Hyolithellus, and /Srt/^ereZZa] are rich in phosphates, and that 

 some of these shells are thick-walled with concentric lamination and 

 with tubes or pores penetrating their walls, suggesting the idea that 

 they may be shells of Worms rather than of Pteropods. I have since 

 compared them with specimens of the singular phosphatic tubes 

 found not infrequently in the Trenton and Chazy formations, and 

 described by Billings under the name Serpulites splendens and 'S. 

 dissolutus. Specimens of these tubes, when sliced, show a structure 

 not fragmental, but composed of very fine concentric laminae, with 

 indications, in some specimens, of minute sinuous tubuli. They are 

 smooth internally, and without show indications of thickened ridges 

 and of transverse lines of growth. One of mj' specimens has been 

 coated externally with a thin layer of some Monticuliporid coral. 

 If these are worm-shells, of which there seems little doubt, they 

 suggest afiinities with the phosphatic HyoliiJieUus and Salterella. 



It may, perhaps, be useful to suggest provisional names for the 

 arenaceous and phosphatic worm-tubes resembling those oiSahellaria 

 and here described. Those from the Black-Eiver formation may be 

 named Sabellarites trentonensis ; and the thick-walled phosphatic 

 tubes, from the Quebec group, S. phospJiaticus. 



* Vol.xxii. p. 608. In the paper of 1866 these are referred to as from 

 the Laurentian of Madoc, Ontario. Since then these beds have been recog- 

 nized as being later than Laurentian, possibly Huronian, and designated the 

 " Hastings group." 



t Vol. xMtii. p. 286. \ Op. cit. p. 288. 



