CARBONIFEROUS AGE. 319 



The iron-ore beds often contain remains of plants, in the form of 

 stems and leaves ; and the concretions, which are of siderite, and of 

 very fine texture, often include portions of ferns, with even impres- 

 sions of the hairs of the surface well preserved ; and also remains 

 of Insects, Spiders, Centipedes, Amphibians, etc., all wonderfully per- 

 fect. 



(a.) Eastern-border region. — In Nova Scotia, at the Joggins, over beds in some 

 places 3,000 feet in thickness, regarded as Subcarbouiferous, there are, according to 

 Logan and Dawson, beds of sandstone, conglomerates, shale, impure calcareous layers, 

 "dirt-beds," and thin coal-beds, of an aggregate thickness of about 13,000 feet. Daw- 

 son gives the same as the thickness in Pictou; and Mr. R. Brown makes the thickness 

 at Cape Breton, above the Subcarbouiferous, 10,000 feet. Of the 13,000 feet at the 

 Joggins, Dawson refers 5,000 to 6,0(>0 feet to the Millstone-grit horizon; 4,000 feet to 

 the "Middle" Coal formation, or "Coal-measures proper," and 3,000 feet, or more, 

 to the " Upper " Coal formation. The last, or part of it, he has since referred to the 

 Permian. The Millstone-grit portion includes thick beds of coarse gray sandstones, 

 containing prostrate trunks of Coniferous trees in its upper and middle parts, with red 

 and comparatively soft beds in its lower; many layers of coaly shale occur through- 

 out, but no coal beds. In the Coal-measures proper, there are dark-colored shales and 

 gray sandstones, with no conglomerates or marine limestones ; they comprise several 

 coal beds, and many "dirt-beds." The uppermost series consists of sandstones, 

 shales, and conglomerates, with a few thin beds of limestone and coal. Many of the 

 beds of sandstone and shale are red. 



Over New Brunswick, the formation is little disturbed; and, according to Dawson, 

 the thickness near Bathurst is 400 feet. The coal beds are very thin, and of little 

 productive value, the thickest but two feet. 



At the Joggins, — of the Cumberland coal-region, — the main coal-bed is five feet 

 thick, with an intercalated bed of clay, a foot or less in thickness. At Pictou, where 

 the beds dip 20°, the average thickness of the main coal bed is 38 feet; 159 feet 

 below this, there is the "deep seam," 15| feet thick; and, 280 feet still lower, the 

 "M'Gregor seam," 12 feet thick. (Dawson.) Dawson states that there are twenty- 

 four feet of good coal in the "main seam;" twelve feet in the "deep seam." The 

 workings of the "main seam " are mostly confined to the upper twelve feet. The bed 

 dips under the Gulf of St. Lawrence : its workable extent has been estimated at thirty 

 square miles. In the Cape Breton region, according to Lesley, there is, at Glace Bay, 

 one bed of coal, ten or eleven feet thick, but of very limited range; another of six 

 feet; and still another of eight feet, besides smaller seams. The whole workable area 

 has been stated at 250 square miles. 



The Rhode Island Carboniferous covers the most of the southern part of the State, 

 and extends northward, through Providence, to the northern border; there it passes 

 into Norfolk County, Massachusetts, and thence eastward, through Bristol County to 

 Plymouth County. The exact limits, east, west, and north, have not been made out, 

 the stratification of the rocks being much obscured by displacements or flexures and 

 metamorphism. There are conglomerates and slates which are supposed by Hitchcock 

 and Jackson to be a part of the formation. The quartzose conglomerate outcrops at 

 Newport and elsewhere, and forms a bold feature in the landscape at "Purgatory," 

 2h miles east of Newport, and at the " Hanging Rocks." The stones vary in size from 

 an inch to a foot, or more. Associated with the slate, there are beds of limestone. It 

 has been supposed that the rocks extend along the valley of Blackstone River to 

 Worcester, near which city there are graphitic slates. 



The principal points where coal outcrops are near Providence, Cranston, Bristol, 

 Portsmouth, Valley Falls, Cumberland, and Newport (a thin bed outcropping on the 

 coast), in Rhode Island; and in Raynham, Wrentham, Foxborough, and Mansfield in 

 Massachusetts. The beds are much broken and very irregular in thickness, owing to 



