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Published online by Cambridge University Press: 01 May 2009
In compiling for the Census Bureau of the United States a small geological map, I had occasion to determine the precise areas occupied by workable beds of Carboniferous Coal. As the sum total is different from that recently stated in the GeologicalMagazine, I have thought a correction desirable; and present a few statements, based upon original authorities, the best within my reach.
page 99 note 1 Geol. Mag., Vol. IX., p. 236. Said to be 100,528 square miles.
page 99 note 2 Geology of Island of Aquidneck, by C. H. Hitchcock. Proc. Amer. Ass. Adv. Sci.,1860.
page 99 note 3 Geology of Pennsylvania, by H. P. Rogers.
page 100 note 1 Geology of Pennsylvania, by H. P. Rogers.
page 100 note 2 First Report upon the Geology of Maryland, by P. T. Tyson.
page 100 note 3 Report to Chesapeake and Ohio R.R., by T. S. Ridgway.
page 100 note 4 Geology of Tennessee, by James M. Safford.
page 100 note 5 Geology of Michigan, 1861, by A. Winchell.
page 100 note 6 Final Report on the Geology of Illinois, by A. H. Worthen.
page 100 note 7 Second Report on the Geology of Indiana, by E. T. Cox.
page 101 note 1 Geology of Iowa, by C. A. White.
page 101 note 2 Second Report, Geology of Arkansas, by D. D. Owen.
page 101 note 3 Texas Almanac for 1861.
page 101 note 4 Ditto, for 1872.
page 101 note 5 Official Report.