452 abstracts: geology 



As it is shown that a flood travels nearly at the rate of the surface 

 velocity, the velocity used in the formula is the surface velocity which 

 is obtained by dividing the mean velocity of the stream by 0.90. 



If K stands for the change of stage per second, V for the mean ve- 

 locity determined during the changing stage, and N for the coefficient 

 for obtaining mean velocity from surface velocity, the formula may be 

 written : 



Qi VSi 



Q2 I „ ~ NK 

 V 



^£1 



Tables and curves are given showing the results obtained by this 

 method on streams varying in size from a canal carrying 50 second- 

 feet up to the Ohio River carrying 365,000 second-feet. 



Conditions requiring the use of automatic gages in obtaining records 

 of stream flow. C. H. Pierce. In 1913-14 the U. S. Geological 

 Survey maintained 1741 gaging stations of which 325 were equipped 

 with automatic gages. The conditions which require the use of auto- 

 matic gages are (1) regulation of the stream by power developments; 



(2) operation of canals and ditches delivering water for irrigation; 



(3) fluctuations due to variation in run-off under natural conditions 

 (a) caused by rain and '(b) caused by melting ice and snow; (4) inac- 

 cessibility of gaging station or lack of reliable observer; (5) continuous 

 record needed for legal purposes; and (6) human fallibility of most 

 gage observers. 



Ground water in Lasalle and McMullen counties, Texas. Alexander 

 Deussen and R. B. Dole. (Abstract in Journ. Wash. Acad. Sci., 6: 

 224-225. 1916.) O. E. M., R. W. D., B. E. J. 



GEOLOGY. — Geology and water resources of Tularosa Basin, New Mexico. 

 O. E. Meinzer and R'. F. Hare. U. S. Geological Survey 

 Water-Supply Paper No. 343. Pp. 317, with maps, sections, and 

 views. 1915. 

 Tularosa Basin is a closed drainage basin in south-central New Mex- 

 ico covering about 6,000 square miles. Its central plain is in part 

 underlain by sediments to depths of more than 1 ,000 feet and is bordered 

 on both sides by fault scarps several thousand feet high. Features of 

 special interest are: (1) basaltic lava sheets of two ages, both Quaternary, 

 with three volcanic cones; (2) recent fault scarps and shore features; 



