50 



THE DESEKT 



The third 

 beach. 



The failing 

 water. 



are many indications in broken pottery, arrow- 

 heads, and mortars that the aboriginal tribes 

 moved down to the new beach and built wick- 

 iups by the diminished waters. And the old 

 fishing-foraging-fighting life was probably re- 

 sumed. 



Then once more the waters went down, down, 

 down. Step by step they receded until the sec- 

 ondary beach was left a hundred feet above the 

 water level. Again there was a pause. Again 

 new beaches were beaten into shape by the 

 waves, new bays were opened, new arroyos cut 

 through from above. The whole process of 

 shore-making the fitting of the land to the 

 shrunken proportions of the lake was gone 

 through with for the third time ; while the 

 water supply from the river or elsewhere was 

 maintained in decreased volume but with some 

 steadiness of flow. Possibly the third halt of 

 the receding water was not for a great length of 

 time. The tertiary beach is not so large as its 

 predecessors. There never was any strong wave- 

 action upon it, its pebbles are few, its faults 

 and breaks are many. The water supply was 

 failing, and finally it ceased altogether. 



What fate for a lake in the desert receiving 

 no supplies from river or sea what fate save 



