258 INDEX TO THE STRATIGEAPHY OF NOETH AMEEICA. 



glomerate and were found to contain numerous stems of encrinites. The dip of the slates is 

 south by west 80°. In front of the encrinal beds, on the long projecting point between the 

 arms of the sound and on the islets at the head of the northern arm, some strong beds of coarse 

 conglomerate are exhibited, which are overlain by black or dark-gray slates, with thin beds of 

 gray sandstone, of from 1 to 6 inches thick. The conglomerate is often very calcareous 'and 

 frequently contains irregular intercalations of limestone. The dip of these rocks is S. 20° 

 E. <60°. Both the conglomerates and associated beds above the encrinal slates were found 

 to be very fossiliferous and in their strike up the southern shore of the eastern arm were there 

 found to pass beneath another mass of coarse conglomerate, which forms the escarpment to the 

 hills which strike in the direction of the point between Pike's and Little Cobb's Arm. The 

 total thickness of this part of the formation, from the junction with the older group to the 

 last-mentioned conglomerate, was estimated to be about 2,000 feet. 



The fossils recognize4 in the strata alluded to appear to be types of the Middle or Upper 

 Silurian series, or about the horizon of the Llandovery group of the British Survey. Some of 

 those previously collected were referred to Mr. Billings, of the Canadian Survey, who identified 

 the following genera and species: Favosites gothlartdica, Heliolites?, ZapJirentis bellistriata, an 

 encrinite referred to the genus Glyptocrinus, a coral referred to the genus Heliophyllum, Orthis 

 ruida, Leptiena sericea or perhaps transversaUs, ventral valve of an orthis like 0. davidsoni, 

 StropJiomena rhomioidalis, Atripa reticularis, Stricklandinia lens, Modiolopsis, Ambionychia, a 

 trilobite, genus Encrinurus, and some others not determinable. 



The conglomerates of the escarpment above mentioned are succeeded by a set of slates 

 which are occasionally slightly micaceous, with beds of quartzite from 2 inches to a foot thick, 

 the strata of which run out upon the coast on the southeast side of Goldson's Sound, usually 

 called Burnt Arm, at the head of which arm the slates pass beneath a mass of limestone, with 

 black slate and trap breccia. At this part trap intrusions are met with and the strata are 

 violently disturbed and altered in some parts in such a degree as to assume somewhat the 

 aspect of the inferior formation, but the occasional presence of fossils, amongst which was one 

 resembling Zaphrentis and some Encrinites, was supposed to indicate a horizon of later date 

 than the Quebec group. 



M 11. ROCKY MOUNTAINS OF BRITISH COLITMBIA. 



In a section examined along the Canadian Pacific Railway McConnell *^^ found 

 the Castle Mountain group (Cambrian and Ordovician) to be succeeded in the 

 eastern ranges of the Rocky Mountains by the "Intermediate" limestone and in 

 the western ranges by the Ordovician "Graptolitic shales" and the "Halysites 

 beds." Neither the "Intermediate" limestone nor the "Halysites beds" is stated 

 to be of widespread occurrence, owing presumably to erosion and unfavorable 

 structural conditions, and they have not been observed in contact. On paleonto- 

 logic evidence the "Intermediate" limestone is assigned to the Devonian, whereas 

 " Halysites catenulatus, Favosites, a coral like Zaphrentis, and some badly preserved 

 brachiopods" indicate the Silurian age of the "Halysites beds." The latter consist 

 of about 1,300 feet of dolomites and quartzites, the quartzite being at the base 

 and the upper part of the formation missing through erosion of the syncline in 

 which the strata occur. 



This isolated occurrence and that in the Finlay-Omenica section (N-0 10) 

 appear possibly to connect the Silurian dolomite of the Porcupine section, Alaska 

 (Q5-6), with the Silurian of Utah.^»«° 



