340 WALTER C. MENDENHALL 



region which he visited and made a number of contributions of 

 permanent value. He explored the Colorado desert, studied the 

 effects of wind erosion in it, examined the old water-line which is 

 so conspicuous a feature on the west side of the valley opposite 

 Coachella and Walters, and worked out correctly both the origin 

 of the lake whose former presence is attested to by it and the cause 

 of this lake's disappearance. 



Professor Blake made three trips along the valley of Carrizo Creek 

 with the expedition, and brought out a few fossils which he collected 

 from one of the flat, sandstone-capped hills on the north side of the 

 valley. These were examined by Mr. T. A. Conrad, who pro- 

 nounced the species new but probably of Miocene age. 



Dr. Harold W. Fairbanks' visited Carrizo Mountain in the early 

 nineties for the California State Mining Bureau, and while the 

 exigencies of publication were such that a complete expression of his 

 observations and conclusions was not possible, his paper is none the 

 less very definite and satisfactory. He made hurried trips to the 

 slopes of Black Mountain, which lies north of Carrizo Creek, and to 

 Carrizo Mountain itself, and made collections from each locality. 

 He described the fossils and the general geology of the district, and 

 mentioned the corals which occur at the base of the sedimentary 

 section. 



Dr. Stephen Bowers,^ of Los Angeles, visited the west side of the 

 Colorado Desert in the summer of 1901, for the Cahfornia State 

 Mining Bureau. At that time there were a number of companies in 

 the district drilKng in the sedimentary rocks for oil. It was in con- 

 nection wdth this oil excitement that Dr. Bowers' visit was made. 

 He secured some fossils from the Carrizo and Black mountain locali- 

 ties which were submitted to Drs. Merriam, Vaughan, and Arnold. 

 The interest aroused by these small collections led to the planning of 

 the trip described here. 



Other writers on the Colorado Desert have devoted themselves to 

 general observations or to the description of particular features out- 

 side the Carrizo Mountain region. Among them may be mentioned: 



1 Fairbanks, H. W., nth Rept., State Mineralogist of California, 1893, 88, 90. 



2 Stephen Bowers, Reconnaissance of the Colorado Desert Mining District, Cali- 

 fornia State Mining Bureau, 1901. 



