One of my favorite classes in college was for a science credit - Geology.
Basically all of eastern WA is one big display of the Great Floods during the last ice age about 15,000 and 13,000 years ago.
granodiorite erratic boulder or basically --
"a rock or boulder that differs from the surrounding rock and is believed to have been brought from a distance by glacial action."
The rumor that the large mound beside our house and why our kitchen is smaller than all the others in the neighborhood is there is one of these boulders.... The neighbor wants to build a fence along that
area and we will have to do some digging, moving of a tree, etc. And if we find the boulder you can bet we'll post pictures.