28 STUDIES IN GEOLOGY, No. i 



evidence of some water action and that the rocks are not 

 volcanic breccias but rather are made up of slightly trans- 

 ported and water-deposited igneous material. 



THE RAMOS SERIES 



A section of the Ramos formation was measured with 

 transit and stadia rod from the Corocoro fault to a thin 

 white horizon at the Libertad mine, 3 km. north of Corocoro, 

 including a thickness of 406 m. The white horizon is cut 

 off by the Corocoro fault in the town of Corocoro. At this 

 point the section was again taken up and measured in the 

 direction N. 66 E., a distance of 3940 m. with transit and 

 stadia rod, including an additional thickness of 3330 m. The 

 total thickness of Ramos beds measured is, therefore, 

 3736 m. In the section are not included beds that have 

 been cut by the fault beneath the lowest outcropping bed of 

 the section nor a considerable thickness of beds east of the 

 measured section which represent overlying beds. The 

 total thickness of the Ramos formation is much more than 

 3736 m. 



SECTION OF PART OF RAMOS FORMATION 

 THREE KILOMETERS NORTH OF COROCORO 



Meters 



Top of section measured at Libertad mine 

 .6 Light-green copper band 

 2.5 Brown sandstone 

 .3 Red shale 

 .9 Thin-bedded brown sandstone with shale laminae between 



beds 



.9 Dark red shale 

 .1 Cop per- stained 

 .4 White shale 

 .2 Red sandy sh'ale 

 .2 Hackly drab shale 

 25.8 Red shale 



.7 Greenish shaly sandstone 

 17.0 Red shale 

 1.4 Gray compact sandstone 



