260 University of California Publications in Geology [Vol. 10 



southern end of the bluffs, both localities were carefully investigated. 

 It was found that at both stations the bones were derived from layers 

 of sand and gravel in the steep faces of the White Bluffs, a little 

 below the middle of the exposed section, and that the strata yielding 

 the fossils are part of the White Bluffs section and not terrace de- 

 posits. The locality one to two miles north of Ringold School is shown 

 near the right-hand end of figure 1 in plate 13. 



There is every reason for considering that the collections secured 

 near Hanford (loc. 3031) and near Ringold School (loc. 2757) rep- 

 resent approximately the same horizon in the White Bluffs sediments. 

 The best preserved specimens from both localities seem to furnish 

 definite evidence of very late Cenozoic age. The ground-sloth jaw 

 from the Hanford locality and the Equus teeth from the Ringold 

 School locality both represent types generally considered characteristic 

 of the Pleistocene. 



As the separation between the Pliocene and Pleistocene is not yet 

 clearly determined on a faunal basis in the Great Basin region, one 

 might admit for the present the possibility of including in the latest 

 Pliocene the faunal stage represented in the White Bluffs exposures. 

 Not even the latest faunas referred to the Pliocene up to the present 

 time includes horses of a stage as advanced as that of the Ringold 

 School fauna, and the evidence on the whole favors Pleistocene rather 

 than the latest Pliocene. 



GEOLOGY 



Stratigraphic Section. — From a point twelve miles above the town 

 of Pasco, in south-central Washington, bluffs several hundred feet in 

 height extend about thirty miles northwestward along the eastern 

 bank of the Columbia River. Because of their light color these 

 magnificent exposures have commonly been known as the White 

 Bluffs. 



The strata in the White Bluffs clearly represent a formation 

 distinct from the Ellensburg, as is indicated by the difference in age 

 expressed in their faunas, and by the physical evidence. The writers 

 propose the name Ringold formation for these beds, from Ringold 

 Post Office, situated at the base of the bluffs. The known thickness 

 of these strata exposed by the downcutting of the Columbia River is 

 approximately 500 feet; as the river has not reached the base of the 

 section the total thickness is not known. The Ringold formation 



5 Russell, L C, U. S. Geol. Surv. Bui. no. 108, p. 99, 1893. 



