298 ROY E. DICKERSON 



at the most to only a few degrees, it is sufficient to cause the lower sandstone 

 layers to be cut off obliquely, and on the cliff sections they are seen to abut 

 against the basal beds of the Tejon [pp. 143-45]. 



The writer cannot see how ''the sandstones below the contact, 

 due to the unco?iformity thicken and thin very noticeably along the 

 strike" but rather thinks that the beds were deposited near shore 

 and that the sandstone lenses into shale or the shale gradually 

 grades into sandstone. If memory is correct, Anderson and Pack's 

 mapping indicates that several comparatively thick members 

 exhibit this same phenomenon on a great scale. Anderson and 

 Pack, F. M. Anderson, Clarke Gester, and J. A. Taff had good 

 opportunities to study this section and as far as I recall none of 

 them recorded any notable dip differences. The writer did not do 

 extended field work in this section, but from what was observed, 

 he believes that careful search will bring to light several erosional 

 unconformities in the region. That is, the Tejon group in this 

 region was deposited under strictly littoral conditions, and from 

 time to time comparatively slight emergences of the Eocene con- 

 tinental strand hne are recorded by these erosional unconformities. 

 Dr. Clark states that the lithology of the sandstones above and 

 below this unconformity are essentially similar. This similarity is 

 so close that a series of hand specimens from above would not be 

 separable from a series from below if the two were mixed. Deposi- 

 tional conditions over the present sites of Simi Hills region and 

 vicinity of Grapevine Canyon are characteristically littoral as 

 indicated by both the fauna and the lithology. 



The fauna of only fifteen species listed by Clark from San 

 Emigdio Canyon on page 149 is entirely too meager upon which 

 to base definite broad conclusions. Of these, eight are new species, 

 one is only generically determined, two are doubtfully referred to 

 described Eocene species. However, it is quite possible that the 

 Turbinolia Zone of the Tejon Group (Meganos Group of Clark) 

 may be present here. 



Dr. Clark assigns the Siphonalia sutterensis Zone of Dickerson 

 to his Meganos Group largely upon faunal grounds, since Turritella 

 merriami, Ancilla (Oliverato) californica, and a few other forms 

 are found at Oroville, Marysville Buttes, in the vicinity of Mount 



