No. 1.] DAWSON — GEOLOGY OP NOVA SCOTIA. 3 



** At Nictaux, 20 miles westward of New Canaan, the first old 

 rocks that are seen to emerge from beneath the New Red Sand- 

 stone of the low country, are fine-grained slates, which I believe 

 to be a continuation of the Dictyonema slates of Beech Hill. 

 Their strike is N. 30 to 60 E., and their dip to the S. E. at an 

 angle of 72°. Interstratified with these are hard and coarse 

 beds, some of them having a trappean aspect. In following these 

 rocks to the S.E., or in ascending order, they assume the aspect 

 of the New Canaan beds ; but I could find no fossils except in 

 loose pieces of coarse limestone, and these have the aspect rather 

 of the Arisaig series than of that of New Canaan. In these, 

 and in some specimens recently obtained by Mr. Hartt, I observe 

 Orthoceras elegantidum, Bucania trilobita, Coniulites Jlexuosus, 

 Sjnrifer rugcecosta ? and apparently Chonefes JVova-scotica, with 

 a large OrtJioceras, and several other shells not as yet seen else- 

 where. These fossils appear to indicate that there is in this 

 region a continuance of some of the Upper Arisaig species nearly 

 to the base of the Devonian rocks next to be noticed." [Some 

 Lamellibranchiate and G-astropod shells in the limestone above 

 referred to, led me to infer that some member of the Upper 

 Silurian series not seen at Arisaig may occur here, and may re- 

 present the Salina formation of the American geologists, just as 

 distinct Niagara fossils, not seen at Arisaig, occur in New Canaan.) 



"After a space of nearly a mile, which may represent a great 

 thickness of unseen beds, we reach a band of highly fossiliferous 

 peroxide of iron, with dark coloured coarse slates, dipping S.30° 

 E. at a very high angle. The iron ore is from 3 to 4|- feet in 

 thickness, and resembles that of the P]ast River of Pictou, except 

 in containing less silicious matter. The fossils of this ironstone 

 and the accompanying beds, so far as they can be identified, are 

 ^piri'fer arenosus,'^ Stropliodonta magnijica, Atri/pa nnguiformis 



* There is in tlie iron ore and associated beds, another and smaller 

 Spirifer^ as yet not identified with any described species, but eminently 

 characteristic of the Nictaux deposits. It is usually seen only in the 

 state of casts, and often strangely distorted by the slaty structure of 

 the beds. The specimens least distorted may be described as follows : 

 General form, semi-circular tending to semi-oval, convexity moderate ; 

 hinge line about equal to width of shell ; a rounded mesial sinus and 

 elevation with about ten [to twelve] sub-angular plications on each 

 side ; a few sharp growth ridges at the margin of the larger valves. 

 Average diameter about one inch; mesial siuus equal in width to 

 about three plications. I shall call this specit^s, in the meantime, 

 S. Nictavensis." [It is nearly allied to the well-known ;Spiri/er vtucro- 

 tiatus of the Hamilton group.] 



