Dr. H. WoodxixLvd — Carhoniferous Arthroijods. 463 



largest yessels resort to ship coal from the adjacent mines. The 

 field is 35 square miles in extent, and is remarkable for the great 

 thickness of its seams. In one section the main seam is 34 ft. 7 in., 

 and what is known as the deep seam is 22 ft. 11 in. thick. Other 

 seams range from 12 feet, 11 feet, 10 feet, 5 ft. 7 in., 3 ft. 3 in.; in 

 all 107 ft. 10 in. of coal have been recorded in this area. 



The Carboniferous formation extends from the high land of 

 Cape George .westward along the whole coast of the peninsula 

 bordering Nortliumberland Strait, and across the country to Chignecto 

 Bay and the Minas Basin, at the head of the Bay of Fundy, 

 occupying Cumberland County and the greiiter part of Pictou, 

 Colchester, and King's Counties. This forms the Cumberland Coal- 

 field and has an area of 430 square miles, worked chiefly at Springhill, 

 where eight seams occur with an aggregate thickness of 52ft. 7 in. 

 of coal. Mines have, however, been opened at several other places, 

 as at lliver Herbert, at MacSan, and at Joggins, whose port and rail- 

 head is at Amherst. 



At the Joggins, on the shore of Chignecto Channel, at the head of 

 the Bay of Fundy, is a unique natural exposure of a continuous section 

 of Middle and Upper Carboniferous strata, which gave Sir William 

 Logan an actual measurement of 14,570 feet. It is a classic region 

 for geologists, and Sir Charles Lyell, who examined it in 1842, and 

 in 1845, and lastly in 1852, pronounced it to be the finest example in 

 the world of a natural exposure of uninterrupted coal-measures in 

 a continuous section 10 miles long. 



The beds, says Lyell,' are all seen dipping the same way, their 

 average^inclination being at an angle of 24° S.S.W., the vertical 

 height of the cliffs being upwards of 300 feet. He observed seventeen 

 trees in an upright position, or, to speak more correctly, at right 

 angles to the planes of stratification; he counted nineteen seams of 

 coal, varying in thickness from 2 inches to 4 feet. At low tide 

 a fine horizontal section of the same beds is exposed to view on the 

 beach. The thickness of the beds alluded to is about 2,500 feet, the 

 erect trees consisting chiefly of large Sigillari(B, occurring at ten 

 distinct levels, one above the other; but Sir William Logan, who 

 afterwards made a more detailed survey of the same line of cliffs, 

 found erect trees at seventeen levels, extending through a vertical 

 thickness of 4,515 feet of strata, everywhere devoid of marine 

 organic remains. The usual height of the bui'ied trees seen by him 

 Avas from 6 to 8 feet; but one trunk was about 25 feet high and 

 4 feet in diameter, with a considerable bulge at the base. In no 

 instance could he detect any trunk intersecting a layer of coal, 

 however thin ; and most of the trees terminated downwards in seams 

 of coal. Some few only were based in clay and shale ; none of them, 

 except Calamites, in sandstone. The erect trees, therefore, appeared 

 in general to have grown on beds of coal. In the under-clays 

 Stigviarice (the roots of the Sigxllaria) abound. 



In 1852 Sir William Dawson and Lyell made a detailed examina- 

 tion of one portion of the strata, 1,400 feet thick, where the coal- 

 seams are most frequent, and found evidence of root-bearing soils at 

 ^ Elements of Geology, 1865, 6th ed., p. 482. 



