IOWA.
The coal measures thin rapidly in a northern direction from Missouri, and in Iowa the pro ductive measures are generally less than 100 feet in thickness, containing only one reliable or work able bed of coal, which ranges from 4 to 5 feet in thickness.
Professor Owen, in his report, says,— "Coal and iron in abundance have been found, and other valuable minerals. The coal measures of Iowa are shallow; much more so than those of the Illinois coal-field. They seem attenuated as towards the margin of an ancient Carboniferous sea, not averaging more than fifty fathoms (300 feet) in thickness. Of these the productive coal measures are less than one hundred feet thick. The thickest vein of coal detected in Iowa does not exceed from four to five feet; while in Missouri some reach the thickness of twenty-five feet (?) and upwards. In quality the coal is on the whole inferior to the seams of the Ohio Valley. To this, however, some very fair beds form exceptions.
"Of this coal-field in Iowa alone, not including its extension south into Missouri, the dimensions are as follows. Its average width from east to west is less than 200 miles; its greatest length from north to south is about 140 miles; its contents, about 25,000 square miles; its extent, mea sured in a direct line, is 200 miles in a northwesterly direction up the valley of the Des Moines." The amount of coal produced in the Great Western coal-field in Mis souri and Iowa is about 500,000 tons per annum.
The coal-fields of Arkansas, Kansas, and Nebraska are but partially developed, and little can be said concerning them of practical value, more than to state their extent and character.
The coals of Kansas and Nebraska are merely the thin western edges of the Great Central coal-field, where only the lowest beds exist, and where frequently only the lowest bed of thin coal is found. In Arkansas the coal measures approach nearly the character of those in Missouri, and stand in much the same relation to the centre of the great basin.
In summing up, we find the total area of productive coal measures within the great Appalachian basin to be 190,000 square miles, exclusive of Texas and the coal that may and does exist on its extreme western edges. This vast area may be properly divided into two distinct and comprehensive fields, under the respective names of the Great Alleghany or Eastern coal field, and the Great Central coalfield. The time has not yet arrived to include the "Great Western coal-field,"—though we have thus denominated the western portion of the Central coal-field.
The division of the great coal-areas described, or the portions existing in the respective States within their limits, may be enumerated thus:—