In that post, I screwed up. There is a Russian coal seam which is 200 m
thick. Wilfred Francis in his book, says that it takes 120 feet of plant
matter to make a foot of coal. At this ratio, I should have said 24000 m of
plant material not 24,000 feet. I didn't correct myself because I really
didn't think it made that much difference. But I was wrong. Sorry for the
confusion.
glenn
Foundation,Fall and Flood
http://members.gnn.com/GRMorton/dmd.htm