Add to ORKGSeveral years ago while studying the coal measures of Iowa and the neighboring states, it was suggested in a general way that the so-called Lower Coal Measures and the so-called Upper Coal Measures eventually might prove to be essentially contemporaneous
The exposed stratified rocks of central Iowa are made up chiefly of Lower Coal Measure clays, shales...
The sandstones under consideration lie in old gorges in Devonian limestone a short distance north of...
Recent analysis of an abundant coal flora dislodged from coalballs,\u27\u27 or sulphur balls of t...
Several years ago while studying the coal measures of Iowa and the neighboring states, it was sugges...
Among a large number of species recently discovered in the lower coal measures near Des Moines are s...
Among a large number of species recently discovered in the lower coal measures near Des Moines are s...
In the general section of the coal measures of Iowa, Missouri and Kansas there are two unconformitie...
For a long time it has been known that in Iowa and the neighboring states to the south a break in se...
For a long time it has been known that in Iowa and the neighboring states to the south a break in se...
For a long time it has been known that in Iowa and the neighboring states to the south a break in se...
Recent diastatic analyses of our Des Moines coal measures, particularly of the great Arkansan centru...
The lower measures of the Iowa-Missouri coal field consist of a series of sandstones, shales, fire c...
Recent diastatic analyses of our Des Moines coal measures, particularly of the great Arkansan centru...
Recent diastatic analyses of our Des Moines coal measures, particularly of the great Arkansan centru...
The exposed stratified rocks of central Iowa are made up chiefly of Lower Coal Measure clays, shales...
The exposed stratified rocks of central Iowa are made up chiefly of Lower Coal Measure clays, shales...
The sandstones under consideration lie in old gorges in Devonian limestone a short distance north of...
Recent analysis of an abundant coal flora dislodged from coalballs,\u27\u27 or sulphur balls of t...
Several years ago while studying the coal measures of Iowa and the neighboring states, it was sugges...
Among a large number of species recently discovered in the lower coal measures near Des Moines are s...
Among a large number of species recently discovered in the lower coal measures near Des Moines are s...
In the general section of the coal measures of Iowa, Missouri and Kansas there are two unconformitie...
For a long time it has been known that in Iowa and the neighboring states to the south a break in se...
For a long time it has been known that in Iowa and the neighboring states to the south a break in se...
For a long time it has been known that in Iowa and the neighboring states to the south a break in se...
Recent diastatic analyses of our Des Moines coal measures, particularly of the great Arkansan centru...
The lower measures of the Iowa-Missouri coal field consist of a series of sandstones, shales, fire c...
Recent diastatic analyses of our Des Moines coal measures, particularly of the great Arkansan centru...
Recent diastatic analyses of our Des Moines coal measures, particularly of the great Arkansan centru...
The exposed stratified rocks of central Iowa are made up chiefly of Lower Coal Measure clays, shales...
The exposed stratified rocks of central Iowa are made up chiefly of Lower Coal Measure clays, shales...
The sandstones under consideration lie in old gorges in Devonian limestone a short distance north of...
Recent analysis of an abundant coal flora dislodged from coalballs,\u27\u27 or sulphur balls of t...