1912] 



Louderback : Pseudost ratification 



23 



If the genetic relationship were not to be insisted upon in the 

 definition of the term stratification, but simply the arrangement 

 in layers or beds, such structures might be referred to as second- 

 ary bedding or secondary stratification. But in the opinion of 

 the writer, it is desirable to limit the term stratification to the 

 genetic types outlined above and to consider the genetic relation- 

 ship as an essential element of the concept stratification. On 

 this basis the term pseudostratification is proposed and will be 

 used in the present paper for any structure that closely simulates 

 stratification as defined above, but which is not the expression 

 of an original laying down of the rock-mass layer upon layer on 

 some preexisting basement or floor. The individual bed-like 

 masses may then be called pseudostrata, any thin subdivisions, 

 pseudolaminae. 



Territory studied. — The territory within which these phenom- 

 ena were particularly studied lies in the central part of Santa 

 Barbara County, California, within the Lompoc quadrangle of 

 the United States Geological Survey, in the hilly country between 

 Los Alamos Valley and Sisquoc Creek (often called "river"), 

 and especially in the vicinity of Cat Canon (Canada del Gato), 

 and the country between it and Poxen Canon. 



General nature of formations involved. — The rocks in which 

 these structures are chiefly developed are massive friable Tertiary 

 sandstones — part of the Fernando formation of the Geological 

 Survey — which here usually show only a light development of a 

 cement and which generally crumble down into smooth, rounded 

 slopes showing no surface exposures and rendering the problem 

 of determining the detailed structure of the region rather 

 difficult. The background of plate 5 illustrates the type of 

 topography involved. Uncemented conglomerate or pebbly 

 sandstone may also show like structures. 



This territory is in part a petroleum producing district and 

 has therefore been subject to considerable "prospecting" in 

 which the determination of the structural details was an import- 

 ant part of the work, and the common absence of exposures 



