74 ' R. W. Chancy 



The forest dominated by the coast redwood is confined to a 

 narrow belt along the coast from central California to southern 

 Oregon. Its more hardy equivalents, among the conifers, extend 

 northward along the coast to Alaska, and occupy the middle 

 levels of the Cordillera, associated with most of the same dicotyle- 

 donous genera. As above indicated, a similar forest occupies an 

 extensive area in northeastern Asia. 



One of the great physical events of later Tertiary time in west- 

 ern America was the outpouring of extensive and numerous 

 sheets of basaltic and other lavas. The wide areal extent of these 

 flows is itself an indication of relatively low relief over much 

 of Washington, Oregon, and Idaho at the beginning of the 

 Miocene. This eruptive activity has continued down into the 

 Recent, but it reached its climax in the middle part of the Mio- 

 cene epoch; at that time there were built up the thick series of 

 flows which have formed the Columbia Plateau and which are so 

 well exposed in the gorge of the Columbia River and in its tribu- 

 tary streams of Oregon and Washington. The Lower Miocene 

 sediments underlying these flows have been exposed by the cut- 

 ting of the John Day and Crooked rivers in eastern Oregon,^' 

 and the record of the Bridge Creek flora, with its dominant red- 

 wood character as above described, has been exposed. During 

 intervals of quiescence between eruptions, there developed a 

 somewhat altered type of forest in Oregon and Washington. 

 This forest, which has been described as the Eagle Creek^^ and 

 the Latah'''"'* floras, differed from the Bridge Creek in the less 

 dominant position of Sequoia, and in the greater abundance of 

 maples, poplars, and such broad-leafed deciduous oaks as Quer- 

 cus pseudolyrata. It is clearly of a more upland type than the 

 flood-plain forest of the Lower Miocene, and appears to have 

 occupied a region of greater relief. Even more definite is the 



