182 Professor H. D. Rogers, on the Geology and [Feb. 8, 



productive coal measures throughout nearly all the diflferent basins, 

 proving tlie universalitj' of the action which attended the commence- 

 ment of that state of the physical geography that witnessed the pro- 

 duction of the coal seams and the sediments which enclose them. 



The eastern half of the continent exhibits five great coal fields, 

 extending from Newfoundland to Arkansas. 1. The first, or most 

 eastern, is that of the British provinces, Newfoundland, Nova 

 Scotia, Cape Breton, Prince Edward's Island, and New Biiinswick. 

 This seems to have been originally one wide coal-field, subse- 

 quently broken up into patches by upheaval and denudation, and 

 by the submergence which formed the Gulf of St. Lawrence: the 

 area of the coal measures of the provinces is probably about 9000 

 square miles, though only one-tenth of this surface appears to be 

 vmderlaid by productive coal seams. 2. The second, or great 

 Appalachian coal field, extends from North-eastern Pennsylvania to 

 near Tuscaloosa, in the interior of Alabama. It is about 875 miles 

 long, and 180 broad, where widest in Pennsylvania and Ohio, and 

 by a careful estimate contains about 70,000 square miles. The 

 narrow basins of anthracite in eastern Pennsylvania, containing 

 less than 300 square miles of coal, are outlying troughs from this 

 great coal-field. 3. A third, smaller coal-field, occupies the centre 

 of the state of Michigan, equidistant from Lake Huron and Michi- 

 gan ; it covers an area of about 15,000 square miles, but it is very 

 poor in coal. 4. A fourth great coal-field is that situated between 

 the Ohio and Mississippi anticlinals, in the States of Kentucky, 

 Indiana, and Illinois. It has the form of a wide elliptical basin. 

 It is about 370 miles long, and 200 miles wide, and contains by 

 estimation 50,000 square miles of coal measures. 5. The fifth, 

 and most western, is the large and very long coal-field filling the 

 centre of the great basin of carboniferous rocks which spreads from 

 the Mississippi and Ozark anticlinals, westward to the limit of the 

 palseoroic region, where the cretaceous strata begin. The coal- 

 field itself has its northern limit on the Iowa River, and its south- 

 ern near the Red River, on the western border of Arkansas. It is 

 in length 650 miles, and in greatest breadth 200 miles. The total 

 area of this great irregular basin is probably not less than 57,000 

 square miles. Three or more small detach( d tracts of coal strata, 

 encompassed by the cretaceous deposits, stretch at intervals south- 

 westward from the southern limit of the longer field through Texas. 

 They are probably extensions of the great field laid bare by denu- 

 dation. Other localities of coal-bearing strata occur in the high 

 table lands on both sides of the Rocky Mountains, and also in the 

 Wahsatch chain of Utah, but it is doubtful whether any of them 

 belong to the true carboniferous series. The aggregate space under- 

 laid by these vast fields of coal amounts to at least 200,000 square 

 miles, or to more than twenty times the area which includes all the 

 known coal deposits of Europe, or indeed, of the whole eastern 

 continent. 



