Page:The Journal of geology (IA journalofgeology21894univers).pdf/423

which have been given. The limits of this paper will not permit anything like a full analysis of the evidence, which must be reserved for some future time. It seems generally, however, to be accepted that sedimentary rocks below the Olenellus horizon shall be considered to belong to the Algonkian. But few forms of the characteristic fauna of the Lower Cambrian are known to extend below this horizon; no fossils have been discovered in the big Cottonwood section in Utah, where 12,000 feet of silicious states and sandstone lie conformably below the olenellus zone. It is safe to assume that through such a vertical extent of rock the typical Olenellus fauna will not range, and consequently part at least must be placed with the Algonkian. That a part of the Vermont rocks immediately below the quartzite may be proven in the future to belong with the quartzite above is recognized, but the trend of the evidence collected by me points toward its classification in part at least with the Pre-Cambrian sedimentary rocks. Without commenting, the reasons for and against this view may be concisely stated, as follows: 1. Extreme diversity of the metamorphic series, or great lithological difference, as compared with the quartzite horizon. 2. Evidence of profound orographic movements in the latter not observed in the former, the folds often occuring overturned to the west. 3. Occurrence of the quartzite reposing discordantly upon granitoid gneiss not far south of the area under discussion and also near by in New York. 4. The near-shore character of the quartzite. 5. The fact that the quartzite does not occur in the heart of or to the east of the range, whereas the series below has been traced across the mountains. 6. In general, the converging of the gneiss-area shown in Hitchcock's map of the State^[1] indicating a northerly-pitching anticline, and in detail shown in small flutings, while the quartzite does not exhibit this feature. 8. The occurrence of undoubted Algonkian rocks near by south of Hoosac Mountain in Massachusetts identified by Mr. Emerson,^[2] who finds Lower