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The foregoing observations and conclusions are only introductory to the great work which yet remains to be done in order to make the natural conditions of the Cretaceous formations appreciated from a utilitarian standpoint. To bring them properly before the attention of the people, it may be proper here to give a brief statement of the economic features now under investigation.

Soil Survey.—As the region under observation is essentially an agricultural one, the first and most important economic problem is a study and definition of the great variety of agricultural soils within its bounds, in order to increase their usefulness and provide for their preservation. With a few unimportant exceptions of transported or alluvial soils existing in the river bottoms of the region, these soils are mostly residual—i. e., the direct product of the weathering of the underlying rock sheets—and consequently they present a great diversity of qualities, varying with the underlying rock sheets. Although, with a few minor exceptions, the soils are mostly calcareous, there are many species of them, and each possesses some peculiar virtue or deficiency for the growth of plant life. A geological map of the region, when published, would accurately show the distribution of each of these diverse soils, with descriptions of their qualities, thus placing our land values upon a more stable and equitable basis, and enabling the farmer to use his soil for plant growth in an accurate and definite manner, and to improve it, if necessary, by an intelligent application of mechanical methods or fertilizers. This classification of soils has advanced so far that in another year it is hoped a final report may be made upon them for the northern area.

The methods pursued in these soil investigations are as follows: The exact geologic origin of the soil is ascertained, by minute observations of the processes of disintegration of the rock or clay from which it is derived, with especial reference to its mechanical condition, chemical composition, and native plant growth.

The average depth and hygroscopic conditions and permeability are also observed. The individuality of a soil having thus been determined, the tracing of its extent is conducted coincident with the tracing of the rock sheet from which it is derived. Due allowance is made for topographic variations; the soils of the Grand Prairie region, for instance, being of little depth except upon the high divides and mesas or in the valleys, the valley slopes being mostly sterile.

So important is this soil survey deemed that it is perhaps no exaggeration to say that, with proper co-operation of our experimental stations, it will