F-FFECT OF CLIMATIC CHANGES ON GLACIATION 561 



seven major terraces at approximately 180, 150, 120, 90, 60, 25, and 15 feet. 

 The GO-foot terrace is especially well developed. Below the 15-foot terrace 

 there are at least five minor strands which appear to represent recent fluctua- 

 tions of Abert Lake, since the vegetation which they carry differs markedly 

 from that of the basin slopes in general. 



"Alkali Laic, Oregon. — The highest terrace was measured by aneroid as 260 

 feet^ above the present bottom of the basin. Below tliis are at least four 

 major terraces and perhaps five. About the present playa are recent strands 

 at 1, 4, 8, and 15 feet. 



"The Warner Basin, Oregon. — Aneroid measurement indicates that the high- 

 est terrace is about 200 feet above the ])resent lakes. Below tliis are at least 

 ten other terraces at elevations of approximately 390, 180, 170, 150, 120, 100, 

 80, 50, 30, and 15 feet. The 120-foot terrace is especially well marked and 

 persistent. Below the 15-foot terrace are at least four recent strands. 



"21ie Catloiv Valley, Oregon. — Waring^ states that there are three well 

 marked terraces, the highest over 75 feet above the present bottom of the valley. 



"TJie Surprise Valley, California. — The highest terrace is estimated by the 

 writer as about 350 feet above the present lakes. Below this are at least six 

 othei-s at about 330, 310, 280, 250, 180, and 150 feet. The 250-foot terrace is 

 very well developed. There are at least three recent strands a few feet above 

 the present lakes. 



"TJie Alvord Valley, Oregon. — Waring^ reports four well marked terraces 

 and two fainter ones, the highest over 100 feet above the present floor of the 

 valley. 



"The Madeline Basin, California. — ^Traces of a terrace system have been ob- 

 served by the writer but have not been studied in detail. 



"Dixie Valley, Nevada. — The highest terrace is 150 feet by aneroid above the 

 present salt marsh. There is one below at about 40 feet, and perhaps one or 

 two between. All terraces are poorly preserved and are represented by rem- 

 nants only. 



"The Columhiis Basin, Nevada. — Conditions in this basin are complicated by 

 considerable differences in level in different parts of the present playa and by 

 the ]j()ssibility of tilting since the lake period. At the south end of the playa 

 the high terrace is 144 feet above the playa. At the north end the. highest 

 terrace found is 104 feet above the playa," the north end of the playa being,, if 

 anything, lower than the south end. The writer is uncertain whether this dis- 

 crepancy is due to recent tilting or to the preservation at the two ends of the 

 basin of fragments of different terraces. Below the high terrace are at least 

 two others, the elevations of which at the south end of the basin are 85 and 55 

 feet. 



"The Big Sniol-y Basin, Nevada. — A system of at least four terraces has been 

 observed by the writer but not studied in detail. The highest appears to be 

 about 50 feet above the present playa. 



"Diamond Valley, Nevada. — Denizens of this valley report to the writer the 



'^ Waring gives this as 275 feet. U. S. Geological Survey, Water Supply Paper 220, 

 1908, p. .31. 



8 11. S. Geological Survey, Water Supply Paper 231, 1909, p. 29. 



« Loc. cit. 



1° Both elevations are from instrumental determinations by the writer and assistants. 



