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Here we have at G the limestones of the coal formation underlying the beds of sand which constitute the exposed edge of the geologic formation on which the Upper Cross Timbers are situated, and which is in fact the receiving area for the artesian wells of Fort Worth and Dallas. These beds are marked fl f2 f3 in the cut and are overlaid in turn by the limestones of the chalk. formation. The inclination of the sand bed is such that at Fort Worth it is reached at a depth of 350 feet, while at Dallas wells must be 750 feet deep to reach it. Knowing now the head of the fountain and extent of receiving area, if we take the known amount of rainfall for the district, we can readily determine the adequacy or inadequacy of the supply for these and intermediate places.

Artesian wells are now flowing in many sections of the State, so many indeed that we can not even enumerate them here, but there are also many other localities where supplies of water can be obtained in this way and these should be brought to notice by the work of the Survey.

DROUTHS.

The drouths which have prevailed in certain portions of Texas for a few years past seemingly possess some periodicity, and their results are so disastrous that it behooves us to put forth most earnest efforts in an attempt to prevent their continued recurrence, a work which to be effective must necessarily be initiated by the geologist and most appropriately under state direction.

The region affected lies between the ninety-seventh meridian of west longitude and the foot of the Staked Plain. It comprises a section of hilly country, which contains much sandy and porous soil, the streams frequently sinking and running under the sands rather than over them, consequently there is a very limited amount of exposed water either in streams or lakes, and also over the greater extent of the region a scarcity of timber growth. And, indeed, it may be said that the same conditions obtain over the entire western part of the state.

This evil is not altogether traceable to the lack of a necessary amount of rainfall, since the records of the Signal Service show that sufficient rain has fallen in every year, save one, to have matured the finest crops, had it only fallen at suitable times. The rain has fallen, but there being no suitable conditions for its retention, it has run off in floods, to carry damage to the lower lying lands and swell the waters of the gulf.

The question, therefore, narrows itself at once to that of a proper distribution of rainfall and the conditions necessary to secure this, or in the event of its impossibility, the storage of the surplus water from rainfall, and holding it so that it may be made available when needed. Thus the matter is resolved into a scientific problem, which, however, when solved, only demands the use of our every day common sense business methods for its proper utilization.

The two elements most serviceable in this solution are the existence of standing or running water and the presence of timber growth.

Although these are not the only essentials, their modifying influence is very marked.

The effect of water, either in running streams, lakes, or ponds, in causing an increase in the amount of rainfall in its vicinity is well understood. By constant evaporation it furnishes abundant moisture to the air and exerts a cooling influence upon the surrounding atmosphere, thus producing meteorologic and electric conditions favorable to rainfall.