448 University of California Publications in Geology [Vol. 11 



thousand feet of deposits which are largely tuffaceous. The section 

 as given by Baker is as follows : 



Feet 



Brownish to red tuff -breccia 



Ashy, tuffaceous beds, quite coarse and poorly assorted up to 75 



Fine, well cemented breccia 40 



Arkose and lava-breccia interbedded with tuff 



Vesicular basalt 



Tuff breccia, fine, gray, poorly stratified 50 



Vesicular basalt 50 



Tuff -breccia, light gray, rather fine, poorly stratified 300 



Gray beds interspersed with layers of dark red 150-250 



Pink-spotted tuff-breccia forming one massive bed 100 



Dark, red breccia with thinner interstratified gray layers .... 250 + 



Dr. J. P. Buwalda, who has made a careful study of the type 

 section of Ricardo, giving especial attention to the highest and lowest 

 portions, has kindly furnished the following description and measure- 

 ments : 



Estimated Section of the Steata Exposed Along Eed Bock Canon 



NEAR BlCAEDO 



Feet 



Extending from the upper of the basalt flows to the top of the exposed 

 section. Beds of yellowish arkosic material, consisting of coarse angu- 

 lar particles of quartz and feldspar and containing a large admixture 

 of angular fragments of granitic rock; muddy sandstones gray, light 

 bluish gray or brown in color and which because of lack of classifica- 

 tion of their materials are indistinctly bedded ; occasional layers of 

 ash, pumiceous material, and brown calcareous material. The general 

 lack of classification and of distinct bedding in the materials and 

 their angular character indicate that they are quite certainly waste- 

 slope and playa lake deposits 1350? 



Columnar basalt, vesicular at upper surface 25? 



Grayish blue arkosic strata, with some clay layers 40? 



Of the section beneath the lavas the lower portion consists principally of 

 bluish arkosic material, the middle portion of tuffaceous strata includ- 

 ing several hundred feet of massive pumiceous tuffs of pink and brown 

 hues, and the upper portion, immediately beneath the lava, consists 

 principally of bluish arkosic beds with some clayey material 1400? 



Mammalian remains are found through the whole of the Ricardo 

 section. At a number of horizons, both above and below the lavas, 

 specimens have been found relatively abundant. It is possible that 

 further collecting along the strike of the beds will disclose other 

 localities in which material will be found well represented at horizons 

 from which as yet little has been obtained. 



