Section I Y, 1889. [ 31 ] Trans. Eoy. Soc. Canada. 



III. — 0)1 New Species of Fossil Sponges from (lie Siluro-Camhrian at LittJe Melis 

 on the Lower St. Laicrence. By Sir J. William Dawson, LL.D., F.R.S., &c. 

 (Including Notes on the Specimens, by Dr. G. J. Hinde, F.G.S.) [Plate III.] 



(Presented U&y 7, 18S9.) 



The specimens described in the following paper show the existence of a rich fauna 

 of siliceous sponges, more especially of the genus Protospongia of Salter, on the muddy 

 sea bottoms of the Siluro-Cambrian pe*iod, and in that early portion of this period repre- 

 sented by the Quebec series of Logan, and probably by the Levis division of the group. ' 

 They are also remarkable as illustrating the structures and habit of these ancient forms 

 and the manner of their preservation. 



The beds at Little Metis have hitherto been very unproductive of fossils, but in the 

 summer of 188*7, Dr. B. J. Harrington, F.GI-.S., was so fortunate as to iind a bed of black 

 shale rich in remains of sponges, hitherto unknown in these rocks, and having made 

 known the fact to the writer, we visited the place several times and made collections of 

 these interesting fossils, which are now in the Peter Eedpath Museum. Subsequently, 

 in the summer of 1888, more extensive excavations were made in the reefs of shale ex- 

 posed at low tide, and it was found that the deposits of fossil sponges are limited, so far 

 as could theu be observed, to two thin bands, each of them scarcely more than two inches 

 in thickness, in the black shales near the head of Little Metis Bay. From these bands, 

 by carefully tracing them along the coast and excavating where the exposures were suffi- 

 ciently good, a large quantity of material was obtained. This was first carefully worked 

 over by the writer and subsequently submitted to Dr. Gr. J. Hinde, F.G-.S , of London, 

 whose resi^lts are embodied in the descriptions of the species in the present paper. 

 Later exploration showed that there are remains of spong-es in other beds ranging 

 through a vertical thickness of aboixt forty feet of the shales ; but not so abundantly as in 

 the layers previously explored. 



Little Metis Bay presents a good section of rocks of the Quebec group, including 

 sandstones, slates and conglomerates similar to those which characterise this series of 

 beds along the south shore of the St. Lawrence. The distribution of these beds is shown 

 in the accompanying map,- from which it will be seen that the general dips are to the 

 south-eastward, and that there appear to be four bauds of sandstone and conglomerate sepa- 

 rated from each other by intervening shales, often of dark colours and carbonaceous, but 

 .sometimes dolomitic, and in many places showing gray and red colours. Assuming the 

 series from the Lighthouse Point to be an ascending one, the thickness of beds exposed 

 at the head of the bay would be more than 3,000 feet; but it is not improbable that 



• Logan, Geology of Canada, 1863; Selwyn, Report Geol. Survey, 1877-78; Ells, Ihkl, 1880-82 ; Lapwortli, 

 Canadian (iraptolites. Trans. Roy. Soc. Can., 188B. 



- For the geographical part of the map on the following page I am indebted to Dr. Ells of the Geological Survey. 



