 The Touchet Formation or Touchet beds consist of large quantities of gravel and fine sediment which overlay almost a thousand meters ( several thousand feet ) of volcanic basalt of the Columbia River Basalt Group in south @-@ central Washington and north @-@ central Oregon . The beds consist of between 6 and 40 distinct rhythmites - horizontal layers of sediment , each clearly defined by its own color and texture .
 hopefully we can find out more about this formation .
The Touchet Formation or Touchet beds consist of large quantities of gravel and fine sediment which overlay almost a thousand meters ( several thousand feet ) of volcanic basalt of the Columbia River Basalt