ALGONKIAN ROCKS IN VERMONT. 407 



which have been given. The limits of this paper will not per- 

 mit 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 dis- 

 covered in the big Cottonwood section in Utah, where 1 2,000 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 recog- 

 nized, 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: i. 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 on Hitchcock's map of the State' 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,^ who finds Lower 



' Geology of Vermont, 1861. 



^See Geological Atlas of the United States, Hawley Sheet, 1892, B. K. Emerson. 

 Members of the Algonkian Period are briefly described on Sheet No. 4. 



