Although only three kinds of coniferous trees have thus far been found in the fossil forests of the park, fully 95 per cent of all the trunks belong to these three species. The preponderance of conifers is probably due to the facts that they were presumably more abundant in the beginning, and that, in general, coniferous wood decays less rapidly than that of most of deciduous-leaved trees. But the conditions were so favorable for preserving any wood that it is perhaps strange that not more trunks of deciduous-leaved trees have been found there. As it is, however, a greater number are known from the park than from any other region. Thus, the Arizona fossil forests embraced only two species of deciduous-leaved trees: the Calistoga (California) wood only one species, and the forest at Cairo, Egypt, only four species. The 10 species of trees represented in the fossil forests of the park are by no means the only fossil plants that have been found. The fine-grained ashes and volcanic mud in which the forests were entombed contain also great numbers of impressions of plants, many of them very perfectly preserved. Most of these are impressions of foliage, such as fronds and leaves, but they include also roots, stems, branches, fruiting organs, and even what is believed to be the petals of a large magnolia flower. About 150 different kinds of fossil plants have been found in the park, 80 in the same beds with the forests, and most of the others in slightly higher and younger beds. The list embraces 10 ferns, among them a fine chain fern (Woodwardia), several aspleniums, and a beautiful little climbing fern (Lygodium). The horse-tails (Equisetum) are represented by 4 species. The conifers include no less than 6 species of pines (Pinus), a yew (Taxodium), and 2 sequoias. These have been identified either from the foliage or the cones, and it is more than likely that some of the specimens may represent organs that belonged to trees represented by the fossil trunks, but as they have never been found connected they have been described separately. The monocotyledons, or plants with parallel-veined leaves, are represented by only a few forms, such as a single large grass (Phragmites), a few sedges (Cyperacites), a smilax, and a curious broad-leaved banana-like plant (Musophyllum). The dicotyledons, or deciduous-leaved plants, make up the bulk of the flora and include walnuts (Juglans), hickory nuts (Hicoria), bay berries (Myrica), poplars (Populus), willows (Salix), birches (Betula), hazel nuts (Corylus), beech nuts (Fagus), chestnuts (Castanea), oaks (Quercus), elms (Ulmus), figs (Ficus), breadfruits (Artocarpus), magnolias (Magnolia), laurels (Laurus), bays (Persea), cinnamons (Cinnamomum), sycamores (Plantanus), acacias (Acacia), sumachs (Rhus), bittersweet (Celastrus), maples (Acer), soap berries (Sapindus), buckthorns (Rhammus), grapes (Cissus), basswood (Tilia), aralias (Aralia), dogwoods (Cornus), persimmons (Diospyros), ash (Fraxinus), and