The lands immediately in the rear of St. Louis, between the Mississippi and the Missouri, below their junction, have an undulated surface, and a deep alluvial soil. Since their occupation by permanent inhabitants, the yearly ravages of fire have been prevented, and a dense growth of oaks and elms has sprung up. In this fact we have a satisfactory explanation of the cause of the present want of forest trees in extensive tracts on the Missouri, which appear, in every respect, adapted to the growth of timber. If these lands, called prairies, were at any former period covered with forests, it may easily be supposed, the {94} yearly devastations of fires breaking out in dry seasons would destroy many of the trees. The forests being thus broken, the growth of grasses and annual plants would be greatly facilitated by the nakedness of the soil, and the free admission of the rays of the sun. Forests attract rain, and impede evaporation; while the reverberation from the surface of vast plains, and deserts, tends to dissipate the clouds and vapours which are driven over them by the winds. In fertile districts like the alluvial lands of the Missouri and Mississippi, a heavy annual growth of herbaceous plants is produced, which, after the autumnal frosts, becomes dry and peculiarly adapted to facilitate and extend the ravages of fire. In a country occupied by hunters, who are kindling their camp fires in every part of the forest, and who often, like the Mongalls in the grassy deserts of Asia, set fire to the plains, in order to attract herbivorous animals, by the growth of tender and nutritious herbage which springs up soon after the burning, it is easy to see these annual conflagrations could not fail to happen. In the Autumn of 1819, the burnings, owing to the unusual drought, continued until very late in the season; so that the weeds in the low grounds were consumed, to the manifest injury of the forests. Large bodies of timber are so frequently destroyed in this way, that the appearance has become familiar to hunters and travellers, and has received the name of _deadening_. After the burning of the grass in the open prairies, the wind, which at that season usually blows with great strength from the north-west, carries off the ashes from the general surface into the hollows and small vallies, thus contributing to enrich the latter at the expense of the former.[50] [50] See Wells _On the Origin of Prairies_, in the 4th number of Silliman's Journal.—JAMES. _Comment by Ed._ "La Grande Prairie," as the French settlers of St. Louis called it, began at Fourth Street of the present city.