CAMBKIAN AND LOWEE ORDOVICIAN. 133 



Dr. Ells accepted the view that the Calciferous fauna occurred in situ in the matrix of the 

 conglomerate, and that the bowlders containing the Potsdam fauna were derived from pre- 

 existing strata. In the next band of conglomerate, above that which forms the ridge on the 

 north side of the cemetery, the matrix also carries Calciferous fossils, and they are also abun- 

 dant in the bowlders. In a search of two days I failed to find a Potsdam fossil at this horizon. 

 •From Dr. EUs I learned that nearly aU the fossils described by Mr. BiUings came from the 

 lower zone, and we found traces of extensive collecting. With these exact data I was enabled, 

 at once, to correlate the lower belt of limestone and conglomerate with the central band of the 

 Phillipsburgh section, where an identical fauna occurs 1,000 to 1,100 feet above the recognized 

 Potsdam sandstone. 



This zone is 600 feet beneath the zone of " Maclurea ponderosa," where Mr. Billings placed 

 the Levis conglomerates. The long period of uncertainty regarding the true mode of occur- 

 rence of the faunas in the Levis calcareous rocks is now terminated, and a fixed datum point 

 secured for comparison with the known section on the shores of Lake Champlain. 



Dr. Ells quotes the greater part of the conclusions contained in Prof. Charles Lapworth's 

 instructive paper on the graptohtes of the "Quebec group." '^ In this the graptolitic zone of 

 the Levis shales is correlated with the typical Arenig of Great Britain and the PhyUograptus 

 beds of Scandinavia. The graptolites of the Citadel Hill or Quebec City strata are correlated 

 with the middle Llandeilo zone of Great Britain. 



The stratigraphic succession, as determined by Dr. Ells, is as follows : 



1. Black, green, and gray ehalee, with, thick bands of grayish and sometimes yellowish-white quartzose sand- 

 stone and occasional thin bands of limestone conglomerate. 



2. Greenish, grayish, and blackish and occasional bands of reddish or purple shales, with thin layers of gray 

 sandstone. Annelid trails (fucoidal markings of Ells) are numerous on the greenish shales. On the south shore of 

 the St. Lawrence below Levis, and also on the south shore of the Island of Orleans, beds of conglomerate occur at 

 about this horizon, in which the Lower Cambrian fauna occurs. 



3. Bright-red shales, with thin bands of greenish and gray shale. 



4. Eed, greenish-gray, and black shales, with interstratified Sillery sandstones. Obolella pretiosa in the upper 

 part near Sillery, and on the south side of the river Obolella pretiosa, Protospongia fenestrata, Phyllograptus typus, 

 Tetragraptus serra, and Lingula quebecensis. 



5. Levis shales and conglomerates of Point Levis. 



6. Black and grayish-striped or banded shales, with the black and graphitic shales and limestone of the 

 Arthabaska and Somerset synclinal, the latter not appearing in the Quebec and Point Levis sections. 



7. The black or brownish bituminous shales and limestones of the city of Quebec and northwest side of the Island 

 of Orleans. The contained fauna is of Trenton-Utica age. 



From the Cape Rouge section and the strata on the south side of the St. Lawrence, 

 Dr. Ells concludes that the evidence afforded by the stratigraphy and the graptolites, deter- 

 mined by Prof. Lap worth, is sufficient to refer the Sillery rocks of 1, 2, 3, and 4 of the section 

 to the Cambrian system, and the Levis beds (5) to the Lower Ordovician. 



The thicknesses of the Sillery and Levis rocks are not given; but Dr. Ells told me that 

 the measurements given by Logan were as nearly correct as could be determined. These were 

 2,000 feet for the Levis shales and 5,000 to 6,000 feet for the Sillery series as now known. '' 



The Oiolella pretiosa ranges through from 1,500 to 2,000 feet of the Upper Sillery, and the 

 lower conglomerate, of 2, occurs in the lower portion of this series. The Cape Rosier Dictyo- 

 nema sociale zone is regarded as the lowest of the graptohtic zones, and to indicate the horizon 

 of the Tremadoc terrane of Great Britain. The Cape Rosier beds are referred to the Upper 

 Cambrian by Prof. Lapworth and Dr. EUs, but with our present knowledge of the Cambrian 

 in America, I would refer them to the Lower Ordovician or to the Lower Calciferous. The 

 occurrence of the typical Calciferous fauna within 100 feet of the base of the Levis series, at 

 St. Joseph de Levis, points very strongly to considering the graptolitic fauna of the Upper 

 Sillery to be of Calciferous age, if a comparison is made with the Phillipsburgh section. 



" Lapworth, Charles, Report on some graptolites from lower Paleozoic rocks: Trans. Roy. Soc. Canada, 1886, pp. 

 167-184. 



b This transfers to the Sillery a considerable portion of the strata originally referred to the Levis. 



