[DAWSON] FOSSIL SPONGES AND OTIIEll ORGANIC REMAINS 



97 



lit the time of tho Quebec Group. Thus, thouirh the coni^lomemte over- 

 lies and irt newer than tho shales holdinj^ sponi^es, the limestone boulders 

 contuincd in it an; of muoh greater atfo. It has loiii^ been well known 

 that similar ai»])oarances oc(^ur in nearly all the limestone confflomerates 

 of the Quebec (rrouj), and at tirst they led to serious difticulties as to tho 

 age of the fornuition. Sometimes they are very deceptive. I have seen 

 in tho conglomerate at St. Simon a slab of limestone, eight feet in length, 

 which might readily, in a limited exposure, 1)0 mistaken for a bed in 

 place, but which is really a Lower Cambrian boulder containing numer- 

 ous fragments of OlenoUus and other ancient Trilobites, and several 

 species of IFvolithes. 



These g. ,t and irregular beds of conglomerate would appear to indi- 

 cate ice-action in the Lower Paheozoic sea, and it would seem \hat the 

 boulders must have been denuded from reefs of older Cambrian rocks 

 now mostly covered up or removed by denudation, while, unlike tho 

 condition of things at tho time of the Pleistocene drift, no Laurentian 

 material seems to have been accessible. 



Up to 1887 the beds in Little Metis Bay had been very unproductive 

 of fossils. They had atlbrded to the late Mr. Eichardson the little Lin- 

 narssonid pretiom, and I had found in the sandstones of Mount Misery 

 and the Lighthouse Point a few fragments of a /{etiolitcs, apparently 

 R. cnsifonnis of Hall, and in the shales near the Lighthouse Point abun- 

 dance of worm trails, some of the typo of that described by the Swedish 

 geologists as Arenicolites spiralis. In so far as these fossils afforded 

 information, they tended to refer the whole series to the lower part of 

 the Quebec Group, and, as it seemed to be an ascending one to the south- 

 west, the impression conveyed to me was that the black shales near the 

 upper part might belong to the base of the Levis series. As already 

 stated, however, the new facts ascertained respecting the position and 

 fossils of the Sillery series now tend to the conclusion that the whole 

 belongs to this lower member. 



For detailed sections of the productive sponge-beds I may refer to 

 my paper of 1889, merely remarking here that in a band of shale, with a 

 few thin layers of dolomite, the whole more than 100 feet in thickness? 

 onlj' three or four layers, each from one to three inches in thickness, 

 have been productive of fossils. 



IV. — General Kemarks on the Fossil Sponges. 



The discovery of fossil sponges at Little Metis Bay was made by 

 Dr. B. J. Harrington, F.G.S., in 1887, in examining loose pieces of black 

 shale washed up on the beach. On searching for these shales in sifu, 

 they were found in low reefs on the shore at about half-tide level, and 

 diligent search disclosed the fact that in a few thin bands of shale sponge 

 remains were abundant, though from the extreme delicacy of their spicu- 



