554 PALJIONTOI.OGICAL REPORT OF GEOLOGICAL SURVEY. 



other places, coal No. 1, B, is from four to six feet thick, arid along 

 the eastern borders of the Illinois coal-field, as at Hawesville and 

 Breckinridge, the same coal is four to five feet in thickness. As far 

 as I have been able to extend my explorations till now, I have not seen 

 any part of the coal-fields, east of the Mississippi, which give indica- 

 tions of having|been separated from the general coal-fields at the time 

 of their formation, except the anthracite basins of Pennsylvania; and 

 I still think, that even these were connected by channels with the 

 general basin, and that these channels have been often obstructed. 

 I hat the high and quiet water of the sea has never covered them, is 

 evident, from the total absence of limestone and shells in their strata, 

 and also from the great thickness and the subdivision of the beds of 

 coal; while in the general basin, the growth of the vegetation of the 

 coal was sometimes stopped by the slow invasion of marine water, in 

 the enclosed marshes of the anthracite fields, the growth of the vege- 

 table materials was continuous for a longer period, and stopped only by 

 the invasion of the sand brought upon them by a greater depression 

 of the whole surface. In this case, we may find the fossil plants to 

 represent the same species in the beds of coevel formation; but these 

 species may be distributed in another manner, viz : appear identical in 

 two or three veins close to each other, when in the general basin, they 

 belong to a single vein. The case is observable near Pottsville, Wilkes- 

 barre, and a few other places, and can be explained only by supposing 

 that while the coal-field was submerged, some disturbance has strewn 

 a bed of sand upon the already growing marshes of the borders, and 

 that the vegetation beginning again, before a general change by de- 

 pression or upheaval, the plants were of the same species as the former. 

 1 still persist in the affirmation of my report to the Pennsylvania geo- 

 logical survey, that the Salem and the Gates veins, as well as the 

 Black and the Lewis veins around Pottsville, belong to the same bed 

 of coal. But if this assertion should be proved a mistake, the identi- 

 ty of the fossils of those veins could not be explained but by the above 

 supposition. 



But, it is asked: if the upraising of the lower formations, which has 

 caused the coal-fields to be separated by about two hundred miles of 

 Devonian and Silurian strata, was posterior to the formation of the 

 coal, what has become of the upraised Coal Measures, and where is 



