May 25, 1906.] 



SCIENCE. 



817 



deposits, and, while a shallow syncline in the 

 underlying limestones was assumed to exist 

 in this block as in the others, no facts were 

 available from which the western limit of the 

 synclinal basin could be determined. The 

 finding of ore in this area was primarily de- 

 pendent upon whether the ore-bearing lime- 

 stones had been eroded oif before the so-called 

 Lake Beds were deposited; in other words, 

 whether the slope of the rock surface beneath 

 these beds is greater than the dip of the lime- 

 stones. 



Mine workings opened in this area during 

 the last ten or fifteen years have disclosed a 

 number of more or less parallel faults by 

 whose displacement the beds have been carried 

 down as though by steeper dips than those ob- 

 served, thus increasing the horizontal area of 

 possible ore bodies. The vertical range of the 

 beds has also been shown to be much greater 

 than was originally supposed, the ore making 

 at several different horizons, called ' contacts ' 

 by the miners. While the possible extent of 

 ore bodies still existing in this western basin 

 is thus shown to be much larger than was 

 originally supposed, no sufficient data from 

 shafts or borings are yet available to accu- 

 rately determine its western limit, though it 

 is probable that to the southwest of the city 

 there is a considerably wider extent of still 

 uneroded limestone than was represented on 

 the sections of the original map of Leadville. 



Mr. Emmons referred briefly to the criti- 

 cisms that have been made of his original 

 explanation of the genesis of the ores, and 

 showed that, while these criticisms are based 

 on misapprehension of his statements, the 

 explanations offered as alternatives are diffi- 

 cult to bring into accord with the observed 

 facts. 



Ohservations on the Contact Deposits at Cop- 

 per Mountain, Southeastern Alaska: Mr. 

 Chas. W. Wright. 



Changes in Level at Yahutat Bay, Alaska, 

 due to 1899 Earthquake: Mr. Ealph S. 

 Tare and Mr. Lawrence Martin. (Pre- 

 sented by Mr. Martin.) 

 This paper will appear in the current vol- 



ume of the Bulletin of the Geological Society 

 of America. Arthur C. Spencer, 



Secretary. 



THE SOCIETY OF GEOHYDROLOGISTS, WASHINGTON. 



The eighth regular meeting of the society 

 was held on April 18, 1906. The following 

 papers were presented: 



Plans for Underground Water Investigation 

 in the West in 1906: N. H. Darton. 



Occurrence of Underground Waters in San- 

 pete and Sevier Valleys, Utah: G. B. Rich- 

 ardson. 



Irrigation, depending on surface streams, 

 has been successfully practised in these fertile 

 valleys since the country was first settled, but 

 the supply is insufficient and attention is being 

 turned to developing the underground re- 

 sources. Sanpete and central Sevier Valleys 

 occupy structural depressions in the plateaus 

 of central Utah. This part of the state is 

 underlain chiefly by strata of Mesozoic and 

 Tertiary age, which lie flat or are only gently 

 inclined, except along lines of upheaval where 

 locally the beds are sharply tilted. The valleys 

 are filled with irregular lenses of gravel, sand 

 and clay, largely, if not entirely, of fluvial 

 origin, which contain abundant underground 

 water. In the lowlands flowing wells are 

 obtained, and over large parts of the valleys 

 pumping plants using electricity developed 

 from the adjacent mountain streams can be 

 operated. Water is also available from bed- 

 rock sources. A remarkable series of springs, 

 yielding in all upwards of 95 second feet, 

 occur along faults at the base of the moun- 

 tains, and in places new flows have resulted 

 from tunneling into the fault planes. There 

 is also the probability of locally obtaining 

 artesian wells from strata that dip towards the 

 lowlands. 



The ninth regular meeting, held on May 2, 

 was devoted to the following discussion: 



Treatment of Water Prohlems in Folios: 0. 



A. Fisher, G. B. Richardson, M. L. Fuller 



and F. H. Newell. 



Mr. Fisher presented the results of a review 

 of the folios of the Geological Survey, point- 



