MRTKOROhOCY WATER. 817 



Geology and underground water i-esources of northern Louisiana and 

 southern Arkansas, A. C. Viv^tcii H . S. (!<<>l. survcii. I'rof. I'lifxr \o. 'i<>. 

 I'll- '/--. /''■•<. •'>/, fw^- -i'^)- — "The presoiit report is liascd on tlic ticid work of 

 llic I'all and winter of 1!)0l2 and I'.H)."'.. snppleniented by sevei-al years' lield woric 

 Willi llie <iei)l(ii;ical Survey ef Ldiiisiaiia and private work in eastei'n Texas. 

 It covers southern Arkansas and uorlliern Louisiana and small portions of 

 adjacent areas iij Mississii»pi and Texas." 



The report contains six chapters, which are brielly outlined as follows: 



(I) Geology, containing a discussion of the geologic history and toi)ograi)liic 

 develo])nient, and including a conii)rehensive statement of the manner in which 

 this portion of tlu> coastal plain was formed and of the broader geologic facts 

 on which the conclusions end)odied in the succeeding chapters are based. 



(12) (Jeneral underground water cojiditions, containing a discussion of the 

 fundamental princii)les governing underground waters and of their aiijilication 

 to this region. 



(3) Methods and cost of well making. 



(4) I'nderground water prosjjccts. by counties, giving well jiredictions and 

 a shoi't discussion of the underground conditions in (>ach county. 



(5) Detailed well and spring records, containing data in regard to wells, 

 arranged in tables, I)y counties, with notes giving sections, etc., being, in fact, 

 an alphabetical arrangement of all tlie well data collected. 



(0) Dictionai-y of altitudes, containing a comprehensive dictionary, arranged 

 by counties, and liased on the precise levels of the United States Engineers, 

 United States ("oast and (Jeodetic Surve.v. and United States Geological Survey. 

 To this net of precise levels the railroad levels have been connected and the 

 corrections determined. 



Geology and underground waters of the Arkansas Valley in eastern Col- 

 orado, X. II. DartoiN ( r. N. (!ci)l. Siirveij, I'rof. I'apcr No. 52, pp. i>0, plx. 2S, 

 filjK. 2). — This report deals briefly with the general geology of eastern Colorado 

 and in d«'tail with the geology and underground waters of the Arkansas Valle.v 

 region. 



The principal water-bearing formation of this region is the "Dakota" sand- 

 stone, iiut wattM's also occur extensively in the alluvial deposits along the 

 valleys, in the sands and gravels mantling parts of the u|»land east of the moxni- 

 tains. and in the sandstones c.t the Fox Hills, Laramie, and overlying forma- 

 tions. Smaller amounts, mostly of bad (luality. occur in the " Red Beds." 



The tpiantity of water available from the "Dakota" sandstone in eastern 

 Colorado is vai'iablc. and in jioi'tions of the region has been found inadequate. 

 As a rule the pressure is too low to sustain a vigorous flow. The largest volume 

 of water has l)een obtained from wells at Uockyford. In some districts the 

 qualit.v of the water is satisfactory, in others the waters are highly charged 

 with nnnerals. 



The bacterial examination of water supplies, W. G. Savage {London: 

 H. K. Lcirlx. llKin. pp. X\ f + 2fn. fif/x. 7.n.— The author of this treatise states 

 his ]inriiiise to be to pi-escnt "a book dealing, not merel.v with the details of 

 practical procedure, but also with the data upon which these methods are based, 

 and with the deductions held t > be justifiable from them. . . . Dogmatic 

 oi»inion has been avoided, the subject being considered from a critical standpoint, 

 and practical conclusions drawn only when they seem justified by the available 

 evidence." 



With the advantage of a ralhei' wide exi)erience in the practical work of 

 examining water supiilies. he ha.s sucx-eeded in bringing into ordered relationshij) 

 within the limits of one compact volume the more important of the large amount 



