424 JOURNAL OV THE WASHINGTON ACAD13MY OF SCIENCES VOL. 11, NO. 17 



Lake cliffs and terraces and beach ridges show that a perennial lake once 

 occupied the largest basin which is now occupied by two playas called Silver 

 Lake and Soda Lake. The maximum depth of this ancient lake, which may 

 be called Lake Mohave, was about 40 feet and the area about 75 square 

 miles. A small but distinct channel at the north end shows that it overflowed 

 toward Death Valley. 



Evidence of another ancient lake, much smaller than Lake Mohave, was 

 found recently in the second basin, which is now occupied by a playa called 

 Cronise Lake. The name Little Mohave Lake is suggested for this lake. 



Buwalda has described Manix Lake that existed in the Pleistocene along 

 Mohave River about 25 miles upstream from Little Mohave Lake. No 

 evidence has been obtained as to the relative ages of these lakes. At present 

 the flood run-off of Mohave River from the San Bernardino Mountains is 

 the only important factor in flooding the playas in the Lake Mohave Basin. 

 Under similar conditions in Pleistocene time, if the ancient Mohave River 

 followed approximately its present course, after Manix Lake was formed no 

 great supply of water would have reached the Lake Mohave Basin until Manix 

 Lake overflowed. If, however. Lake Mohave was wholly contemporaneous 

 with Manix Lake, the precipitation in the area directly tributary to the Lake 

 Mohave Basin below Manix Lake must have been considerably greater 

 than it is today. Evidence on the relative age of these lakes will aid in inter- 

 preting the climatic conditions under which they existed. 



In January, 1916, floods from Mohave River covered Silver Lake playa to a 

 depth of 8 or 10 feet. When the water disappeared 18 months later, maay 

 dead fish were found on the playa. These had been carried at least 25 miles 

 from their regular habitat along the river. Fish remains have been reported 

 under similar conditions on the other desert playas. Such occurrences 

 show that fresh-water remains in desert deposits do not necessarily indicate 

 the existence of an ancient perennial fresh- water lake. 



The fish belong to two species. — One the common catfish, and the other 

 Siphateles mohavensis, which is found only in Mohave River. Other species of 

 the latter genus live in the San Joaquin River, Owens River, Lahontan, and 

 other systems. It is not certain how Siphateles mohavensis reached its present 

 habitat, but it is suggested that members of the genus may have migrated 

 from Owens River to Death Valley, through a chain of lakes described by 

 Gale, and thence up the ancient Mohave River, through Lake Mohave. 

 If such a migration took place the same genus ought to be found in Amargosa 

 River which now enters Death Valley. 



O. E. Meinzer: Ground-water problems in the Hawaiian Islands. 



Mr. Meinzer spent February and March, 1920, in the Hawaiian Islands 

 to start a systematic geologic and ground-water survey of the Islands. Work 

 was in progress in 1920 in the Kau district on the Island of Hawaii, by W. O. 

 Clark and L. F. Noble, and in the Honolulu district by H. S. Palmer. 

 The present paper outlined the ground-water problems as seen in this visit 

 of two months. 



The rocks of the Hawaiian Islands consist chiefly of small irregular bodies 

 of extrusive lava which is very permeable. This great permeability results 

 in (1) heavy absorption of rain by the rocks, (2) flatness of the water tables, 

 (3) scarcity of springs and streams, (4) large yields of aquifers, and (5) large 

 yields and specific capacities of wells. 



The ground water can be divided into two kinds : high-level water and low- 

 level water. The low-level water does not occur much above sea level; the 



