1913] 



Louderback : 



The Monterey Scries 



227 



the Temblor basin. Along this eastern border region the rocks 

 developed are chiefly terrigenous while the "Monterey" (by 

 which of course he really means an upper diatomaceous member, 

 although he evidently has in mind an ideal time interval) "is 

 either absent, or is present in a reduced or disguised form" — 

 "disguised form" is, I believe, a very appropriate expression. 



"The explanation of this interesting fact is to be found no 

 •doubt in the diastrophic record of the times. The subsidence 

 that inaugurated the occupation of this basin by Temblor sedi- 

 ments continued without interruption until middle Miocene time. 

 It then paused, and on the eastern and northern borders of the 

 basin the shore lines remained stationary throughout the epoch 

 of the Monterey. In these parts, therefore, sedimentation was 

 nil, while along the western borders subsidence went on without 

 cessation, and sedimentation was therefore continuous." 



"It is unnecessary to suppose that there was any elevation 

 and denudation of the older Miocene during the Monterey epoch, 

 either in the Kern River area or elsewhere, and no such dis- 

 turbance seems probable. The facts appear to indicate merely 

 an epoch of stability along the eastern and northern shore lines 

 of the basin, along which, therefore, the conditions were unfa- 

 vorable for the continued accumulation of any class of sedi- 

 ments" (pp. 110, 111). He also considered that the climates of 

 the Temblor and Monterey epochs were different, the diatoma- 

 ceae, foraminifera, gypsiferous strata and lack of terrigenous 

 sediments, in the latter, indicating an arid climate (p. 111). 



The writer inclines towards a simpler explanation than the 

 one given by Anderson, which requires the interior edge of the 

 basin to sink only during lower Miocene and to stop sinking 

 in middle Miocene while the depression of the coastal portion 

 continued. It looks very much like the result of simple pro- 

 gressive subsidence with minor oscillations. In the gradual trans- 

 gression of the sea, terrigenous sediments (generally sandy or 

 pebbly) were almost everywhere laid down and only with in- 

 creasing depth and distance from the shore line do we get organic 

 deposits. Naturally the edges of the basin when at its period 

 of greatest areal extent must have been in the littoral zone and 

 could have received only terrigenous or chiefly terrigenous de- 



