5. _The same fact may be inferred from the immense amount of vegetable matter which was necessary to supply the materials for the coal measures._ This is an irresistible argument in view of the _immense amount_ of coal in the bowels of the earth, which must be of _vegetable origin_. Because at the ratio of vegetable product of _our age_, the earth would not produce a sufficient amount to form the coalbeds, short of millions of years. The _vegetative power_ of the earth, therefore, must have been anciently very much greater than at present, which could only be on the supposition of a _warmer_ and more moist climate. Moreover, the fact that tropical plants are known to have contributed almost entirely to the formation of coal measures in the _northern latitudes_, is proof direct. This is clear from the fact that their roots, stems, leaves, flowers, and fruits are found impressed on the coal, in such a manner that there can be no mistake; and the _perfection_ of the impression forbids the supposition that they were _transported_ thither from tropical climates. “Brown coal and black coal, the former sometimes called wood coal, is found chiefly in diluvial or alluvial ground. It contains, besides charcoal and bitumen, _various vegetable principles, and the branches or trunks of trees_ partially decomposed, _which mark the origin of this kind of coal_.” _Bakewell’s Geology_, p. 111. “Wood coal, or brown coal, is found in low situations and appears to have been _formed of heaps of trees_ buried by inundations under beds of clay, sand, or gravel.--In some specimens of this coal the _vegetable fibre, or grain_, is perceptible in one part, and the other part is reduced to coal.” _Ibid_, p. 121. “In wood coal we may almost seize nature in the fact of making coal, before the process is completed. These formations of coal are of far more recent date than that of common coal, though their origin must be referred to a former condition of our globe, _when the vegetable productions of tropical climates flourished in northern latitudes_. The _vegetable origin_ of common mineral coal appears to be established by its association with strata _abounding in vegetable impressions_, by its close similarity to wood coal, (which is undoubtedly a _vegetable product_) and lastly by the decisive fact, that some mineral coal in the Dudley coal-field is _entirely composed of the layers of mineralized plants_.” _Ibid_, p. 122. “When we see the multitude of reeds filled and surrounded with sandstone, having their thin scaly bark _converted into a true coal_, it is _impossible to doubt of its vegetable origin_.” _Ure’s New System Geol._ p. 166.