. The geological history of plants. Paleobotany; 1888. THE CARBONIFEROUS FLORA. iir covery has since been extended to all the coal-fields of Europe and America, and it is a perfectly conclusiye fact as regards the origin of coal. Each of these "under- clays," as they are called, must, in fact, have been a soil on which grew, in the first instance, Sigillarise and other trees having stigmaria-roots. Thus, the growth of a forest of Sigillariw was the first step toward the accumu- lation of a bed of coal. More than this, in some of the coarser and more impure coals, where there has been


. The geological history of plants. Paleobotany; 1888. THE CARBONIFEROUS FLORA. iir covery has since been extended to all the coal-fields of Europe and America, and it is a perfectly conclusiye fact as regards the origin of coal. Each of these "under- clays," as they are called, must, in fact, have been a soil on which grew, in the first instance, Sigillarise and other trees having stigmaria-roots. Thus, the growth of a forest of Sigillariw was the first step toward the accumu- lation of a bed of coal. More than this, in some of the coarser and more impure coals, where there has been sufiBcient earthy matter to separate and preserve impres- sions of vegetable forms, we can see that the mass of the coal is made up of flattened Sigillarm, mixed with vege-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Dawson, John William, Sir, 1820-1899. New York, D. Appleton and Company


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