Page:Popular Science Monthly Volume 23.djvu/537

Rh south as Prince's Bay; and the cretaceous, which occupies the remaining small area in the southern and western part. This latter is a continuation of the New Jersey clay-beds. The geological line of separation between the two formations is not always very distinct, but the limits of the different species of plants mark it in unmistakable characters. The two floras are remarkably distinct. That one belonging to the cretaceous is well represented by ''Arctostaphylos, Uva-ursi, Aster concolor, Pinus inops, Quercus Phellos, Quercus nigra, Lycopodium inundation, var. Bigelowii,'' and many more of the pine-barren plants. Thus far I have never found any of these species to have crossed the line of the drift, but in their stead will be found Pinus nigra, Quercus alba, Quercus rubra, etc., and the majority of those plants which grow in the vicinity of New York Island and up the Hudson."

The Mississippi region embraces the lowlands bordering the Gulf of Mexico from Middle Georgia to Texas, and extending up the Mississippi and its branches to latitude 30°. It is a continuation of the Carolinian region, its characteristic trees growing from the Gulf of Mexico to the coast of Maine. It is composed of the same tertiary and cretaceous beds of the Carolinian region, with a few patches of alluvial deposit along the coast.

The Florida region is well marked and peculiar, being entirely coral alluvial. It has the peculiar flora of that formation found all over the world. Some of its plants are found farther north; but small beds of alluvial are not uncommon along the coast as far north as New Jersey.

The Campestrian province might be considered as one region, but Cooper has divided it into five. The Saskatchewan region, embracing all north of latitude 49°, together with the basin of the Red River of the North, has some spurs of the Canadian region running into it, and consequently some of the Canadian species are found on them and on the adjacent Silurian and other formations. This region has no characteristic trees of its own. The Illinois region lies between latitudes 46° and 38°, running west to longitude 101°; on the east it is bounded by the forest provinces. It is a continuation of the Ohio region, being underlaid with the same beds of Silurian and carboniferous deposits, with cretaceous and tertiary beds on the west. But here a new feature enters into the geological characteristics. The loess or lacustrine deposits which cover the whole province from four to one hundred and fifty feet, though devoid of trees, have a peculiar flora, composed largely of compositæ, and being one of the latest of geological deposits, they furnish the most recent botanical species of the composite. None of the compositæ have yet been found in any of the fossil flora; hence it has clearly appeared upon the earth since the Tertiary period. Another remarkable fact is that on the eastern side of the Illinois region where