SCIENTIFIC BACKGROUND 147 



that this fault-trend continues indefinitely south of 

 east across Arizona below the southern edge of the 

 Colorado Plateau into New Mexico. But little more 

 than the mere fact that it exists can now be definitely- 

 stated regarding it. 



THE EAGLE MOUNTAIN LINEAMENT 



Another line of east-west faulting of the Desert 

 Side, as indicated in the topography, lies about fifteen 

 miles south of and parallel to the Pinto Mountain fault, 

 and corresponds to the rectilinear north side of the 

 Eagle Mountains. It passes through the Pinto Basin 

 and the middle of the Little San Bernardino Highland. 

 Its westward continuation, if it could be traced, would 

 pass by the northwest end of the Indio Hills and to a 

 connection with the east end of either the Lawrence 

 or Banning faults of San Gorgonio Pass. 

 THE OROCOPIA LINEAMENT 



Probably a third rectilinear east-west rift of the 

 Desert Side of the Transverse Belt might be called the 

 Orocopia Lineament. It may be indicated by a nearly- 

 straight line ninety miles long, drawn between Coa- 

 chella on the west and Blythe on the east. Actual 

 fault contacts, such as would cheer the heart of those 

 geologists who demand more than physiographic tes- 

 timony\ may be seen in the Mecca Hills on the road 

 from Mecca to Blythe. From thence the eastward 

 extent of the rift is strongly suggested by escarpments 



'A proper appreciation of the great master fault lines of Southerni Cali- 

 fcrnia has been long delayed owing to the oppositions of a school of geologists 

 who oppose the direct testimony of the physiography as expressed in nature 

 and upon good topographic maps and as ha=; been long alleged by the writer, 

 "Any one," remarked an opponent, "can take a topographic map of Southern 

 California and draw lines along the boundaries of its major units and 

 call them faults." He little realized that his word; spoken in unfriendly 

 criticism, expr^^sed the sreat truth which I have endeavored to inculcate for 

 years, and which, until the recent coming to California of Professor W. M. 

 JDavis, the father of physiographic study in Ani'^rica, was but little appreciated. 



