g CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



STRUCTURE 



The entire series of Oligocene and Eocene deposits involved 

 in this region exists in the form of a northeasterly low dipping 

 monocline. It is probably the southwestern limb of a broad 

 syncline, the northeastern limb of which occurs in the region 

 around Chehalis and Centralia. There are minor undulations 

 in the northeasterly pitch of the strata between Olequah and 

 Winlock. In the vicinity of Vader a low, shallow anticline has 

 been developed whose axis trends N. 30° W. It crosses Ole- 

 quah Creek one-half mile north of Vader. The strata on the 

 north side of this minor fold dip to the northeast at an angle 

 of 40° and on the southwest side at an angle of 15°. One thou- 

 sand feet south of the axis of the minor anticline there is a 

 shallow syncline having approximately the same trend as the 

 anticline. At the point where the axis of the anticline crosses 

 Olequah Creek the same marine strata are brought to the sur- 

 face which occur to the southwest of Vader along Stillwater 

 Creek above its junction with Olequah Creek. 



A glance at the map accompanying the report indicates 

 several apparent discordances in strike and dip in the vicinity 

 of Olequah. It might be inferred that the strata had been 

 greatly disturbed and faulted. However, such is not the case. 

 There are simply minor undulations in strike and dip along the 

 prevailing direction of strike. The variations as shown upon 

 the map were inserted for the purpose of emphasizing these 

 irregularities. 



FAUNAE RELATIONS 



In constructing the stratigraphic section accompanying this 

 paper an attempt was made to arrange the fossil localities in 

 their stratigraphic sequence. The following localities range 

 from the base near Olequah to the upper portion of the sec- 

 tion near Winlock: Localities Nos. 299, 5, 236, 298, 294, 

 294a, 241, 238, 301, 231, 234, 300, 295, 1, la, 232, 233, 239, 

 292 and 229. 



Localities 299 to 301 contain a marine fauna. Localities 

 231 to 300 contain a brackish water fauna. Localities 295 

 and 303 contain a freshwater fauna. Localities Nos. 1 to 233 



