The chief coal-producing area is the Powder River Basin, which lies in northern Wyoming and southeastern Montana. Coals of Cretaceous age are present http://www.wsgs.uwyo.edu/coalweb/library/coaltime/cret.aspx which is 144 to 66 million years ago.
It is interesting to see that 66 million years ago the earth was
http://commons.wikimedia.org/wiki/Image:Phanerozoic_Climate_Change.png experiencing a hotter climate. We know that life flourished upon earth because coal is the residue of that 66 million year old life. See http://en.wikipedia.org/wiki/Geologic_temperature_record
Another useful chart of earth temperature http://en.wikipedia.org/wiki/Image:All_palaeotemps.png
There is a large body of documents from the 1920’s through the present day which are important for researching and understanding the history and development of the Fischer-Tropsch and related processes. The purpose of this site is to make these documents available in electronic media and in a centralized location. http://www.fischer-tropsch.org/
