THE CAMBKO-SILURIAN, OK ORDOVFCIAN. 25 



have evidently experienced much mctamorphism, have been found at 

 one locality to contain fossils of Trenton age equivalent to Bala and 

 Llandeilo. Similar rocks come out from beneath Silurian beds in 

 various parts of the hilly districts of Nova Scotia.* They resemble 

 the Cumberland Ordovician more nearly than otlicr British develop- 

 ments of these rocks. In the continuation of these beds in Xorthcrn 

 New Brunswick Graptolites were discovered some years ago by Mr 

 Robb and Dr Ells, of the Canadian Geological Survey, and are 

 believed to be of Upper Ordovician age. 



VIL THE CAMBRIAN. 



For a long time the base of the Palaeozoic, in the eyes of most of 

 the geologists of America, was the Potsdam Sandstone, which over 

 wide areas of Canada and the United States rests unconformably and 

 directly on the Laurentian. 



The marginal areas of the continent have since afForded a great 

 series parallel to the Cambrian of Wales and of Scandinavia. 



In southern Newfoundland the Huronian rocks, or the Signal-llill 

 red sandstones and conglomerates overlying them, are succeeded, 

 according to Jukes and Murray, by a thick formation of sand.stones 

 and slates with a little limestone and conglomerate, and near the base 

 of this the great Paradoxides Bennetii and other forms of like age 

 are found. These are Middle or Lower Cambrian, and obviou.sly 

 parallel with the beds holding the rich fauna of this age in New 

 Brunswick, originally described by the late Prof. Hartt,-)- and more 

 recently and more fully by Mr Matthew. \ The strata holding these 

 fossils in Newfoundland have conglomerate, slate, and limestone 

 below, and a great thickness of variously coloured slates above, over- 

 lain by sandstones and slate. Very similar beds constitute the lower 

 Cambrian series of St John, New Brunswick. 



There exists in southern New Brunswick a series of red, purple, 

 and gray conglomerates and sandstones not unlike the Signal-llill 

 .series, unconformable to the Huronian below and the Paradoxidcs- 

 beds above, and holding not only worm-tracks, but Linguloid shells. 

 These are regarded by Matthew as a basal Cambrian series, equiva- 

 lent to the Caerfai group of Hick.s, while above this are the equiva- 

 lents of the Solva and Menevian groups of the same geologist, corre- 

 sponding in mineral character and fossils so closely as to indicate 

 portions of the same sea-bottom. § The Briantrec slates in Ma.ssa- 



* (iuart. Journ. fleol. Soc. 18.00. Aciidinii Geoloj^y .niul Siipplciiu'iit. 



t Acadian Geology, 18G8. | 'I'nins. Koyal Society of I'aiiaila, ISSf) to 1888. 



^ Matthew, Canadian Record of Science, 1888. 



