20 PROCEEDINPS OF THE CANADIAN INSTITUTE. 



Prof. T. S. Hunt, of Montreal, is disposed on chemical and lithological 

 grounds to assign both this and the following to the Huronian. The next is a 

 Siliceous Argillyte (F) passing into an impure Serpentine, with, however, 

 some seams of Talc and Precious Serpentine. The relative age of this and 

 the preceding series is difficult to make out. However, together with frag- 

 ments of A, C, and E, it seems to have constituted an island some four miles 

 in diameter in the midst of the Carboniferous marsh or estuary. All the 

 rocks described above are presumably of Pre-Carboniferous age, and upon the 

 different members of this series, for they do not seem to have been uniformly 

 deposited, the Carboniferous rocks were laid down. The lowest bed of Car- 

 boniferous age is a conglomerate of fine Quartz pebbles with some argillaceous 

 matter, metamorphosed into a dark, compact, siliceous rock, containing here 

 and there a layer of black slate with Annularia longifoUa (G). This probably 

 belongs to the "Millstone Grit." The overlying bed is a Sideritic Argillyte 

 (H) — a finely laminated slate generally with minute nodules of carbonate of 

 iron with a crystalline structure. Then a thick bed of coarse conglomerate 

 (I), the pebbles and boulders of Avhich consist of a micaceous Quartzite, and 

 contain in some localities Lingulte. Minute crystals of Magnetite abound in 

 the cement of this conglomerate. The pebbles are often coated with scales of 

 Mica, and the shells of the Lingulse are sometimes plumbaginous. Lastly, 

 we have the Coal-measures proper consisting of alternating conglomerates, 

 sandstones, clay slates and Mica-schists, together with several seams of 

 plumbaginous Anthracite (J). About sixty species of coal plants occur in the 

 slates of this series — mainly of the genera : Annularia, Calamites, Lepido- 

 dendron, Neuropteris, Odontopteris, Pecopteris and Sphenophyllum. The 

 impressions are sometimes coated with Talc or Pyrite. The latest analysis of 

 this coal * afi'orded the following extremes in nine analyses : Carbon 67 — 79 

 %, Ash 11—17 %, Volatile combustible 4^—7^ %, Water 2^—10^ %. The 

 Ash contains from 50 — 75 % of Silica. This coal, as stated by Dr. Emmons, 

 possesses the property, after being dried at 115'' Centigrade, of absorbing, 

 when exposed to a N.W. wind, over 13 % its own weight of water, and, when 

 placed over water, 22^ %. Veins of Quartz and of Asbestus traverse the coal 

 seams. 



The Pre-Carboniferous beds measure at least from 4,000 to 7,700 feet, the 

 Carboniferous from 4,000 to 5,500, and in other parts of the basin perhaps 

 8,000 feet. All the beds have been folded parallel to the Appalachian chain, 

 and the last flexure probably took place at the close of the Carboniferous 

 Period. The beds were also flexed, though on a much smaller scale, in the 

 npposite direction, indicating a pressure operating N.N.E. — S.S.W., as well 

 as one W.N.W.— E.S.E.] 



In the western part of the basin, along the West Passage of 

 N^arraganset Bay, the strata of the Coal-measures are much disturbed^ 

 being in places vertical or folded over upon themselves. In accord- 



■* Arthur B. Emmons, Notes on the Rhode Island and Massachusetts Coals. Transactions of 



the American Institute of Mining Engineers, Sept., 1884. 



