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



of the town of Vacler ( formerly known as Little Falls and So- 

 penah) the Cowlitz River swings from its east- west course 

 and assumes a due north-south direction. One mile south 

 of Vader, Stillwater Creek enters Cowlitz River and about one- 

 fourth mile south of the town, Olequah Creek joins Stillwater 

 Creek. From this point Olequah Creek extends almost due 

 north to Winlock. The Northern Pacific Railway between 

 Portland and Seattle follows the valley of this creek. 



The drainage of the entire area is southerly to the Colum- 

 bia and the hills on either side rise gradually into a rolling tim- 

 bered country. Eocene strata away from the banks of the 

 creeks are not exposed but are covered with gravels and sands 

 formerly deposited by Cowlitz River. 



STRATIGRAPHY 



In the examination of this region a transit survey was made 

 of Stillwater and Olequah creeks and the position of all fossil 

 localities as well as observations taken upon strikes and dips 

 definitely located. These data have been plotted upon the map 

 accompanying this report. 



Between the towns of Castle Rock and Olequah only four 

 exposures of Eocene strata are known to occur. They consist 

 of dark gray, sandy shales with intercalated basaltic flows. 

 Two miles north of Castle Rock and 2,000 feet south of the 

 Northern Pacific Railway bridge over Toutle River, there is 

 an exposure in the railway cut composed of bedded tuffaceous 

 materials together with sedimentary deposits of worked over 

 basalt. These beds have a strike of N. 75° E. and a dip of 

 5° N. W. They are overlaid with Pleistocene deposits com- 

 posed of sand and gravel intermixed with angular fragments 

 of basalt, which appear to have been derived by rapid erosion 

 from nearby bluffs of Eocene basalt. 



From this point northerly for a distance of two miles the 

 only exposures along the railway consist of Pleistocene grav- 

 els and sands. One and two-thirds miles north of the Toutle 

 River bridge Eocene rock outcrops occur for a distance of 450 

 feet. The bluffs at this point are about 60 feet high and con- 



