Arizona republican., 1904-07-10
UNDFRGROUNDFLOW
Geology of the Salt River
 Valley Outlined
Synopsis of the Conclusions of Geolo- sist W. T. Lee After Comprehen- sive Study of Local Conditions.

The following article should prove an interesting one to every water user in this valley and every person in anyway concerned by its water supply or in the study of it's water resources. Further than that its perusal will not be a waste of time for those engaged in mining in the southwest or in any line of activity in which a Knowledge of geologic conditions is desirable. though 4ts connection with mining was not considered in it's preparation and is of only general interest. It is a water story.
 For the last fifteen months, Mir. w. T. Lee, geologist of the reclamation service, has been engaged in a scien- titic study of this valley, with special respect to the knowledge that may be secured concerning the underground water supply. through a careful noting Of geologic conditions, the demonstrate ing of theories where practicable, and in other instances by comparison with demonstrations elsewhere. MT. Lee is now finishing up his work 1hd prepar- ing for submission to his superiors. his report of the work done It will be voluminous, covering a great number O. typewriter pages, together with many illustrations. What follows is a brief summary of his deductions. tell. ing something of the geological history of the valley; the method of the forma- ton of those strata nearest the surface with which the inhabitants of the pres ent day are most concerned.
 Should the reader take exception to any of MT. Lees conclusions, on tue ground that the proof of their correct ness is not in all cases set forth in this article, he is asked to remember tbat space does not warrant it, those things being set forth in his report. The at tempt here is to record findings with such proofs as are easily given and as are necessary to connect the narrative.
 The great continental plateau. that covers the western third of North America passes to the northeast of this section. Its western escarpment, can be readily traced northeast of Tonto basin. The attitude of the sed- mentary formations of that plateau. IS noted at it's border bluffs and else where, indicates that formerly they extended over this region and were carried away by erosion. the result of which is the low lying country of which the Salt river valley is a part. The whole country to the southwest cf that escarpment, is due in large meas ure 10 the surface formations baiRg carried away by water. Other factors such as faultins;, have come in, to in fluence surface formation in this region in the making of valleys and hills, but it is MT. Lees opinion that the valleys and hills are mainly the result of sro- sion. This being the case, in fo:m r ages a deep wide valley was cut through the region, now drained by Salt river. That valley subsequently, sunk some hundreds of feet in places at least, causing the river debris to ac- cumulate in the valley for the surface of the ancient valley is what now forms the bedrock of the present day. A proof of it is cited in the Mcqueen well which was sunk to a depth of over 1900 feet and no bedrock was encountered. As 1900 feet is lower than sea level and rivers must be somewhat higher to perform their function, the argument Is proved that at sometime the bedrock of the original river, in the vicinity of Mesa. at least, must have been de- pressed.
 The formation of other valleys in western Arizona, all over the region west of the great plateau mentioned in the beginning, was similar, the fact be- ing demonstrated in the same way and multiplying instances proving the cor rectness of the theory. Cases in point are at Yucca in the Sacramento valley of Mohave county where bedrock was not encountered at the depth of 1000 feet and along the San Pedro river where wells sunk to the depth of 800 ! feet failed to strike bedrock. MT. Lee says that on his recent trip up the Colorado river he noted detrital mat ! ter at an altitude of 2,400 feet above the present river bed and it continues below the water for an unknown dis