Just beyond this area of housing, sits a lonely boulder from Montana on the Badger Coolee which isn't far from the Wallula Gap(red arrow), it was dropped by an ice berg during the Ice Age Floods that hit this area over 10,000 years ago. While this pic doesn't show this monster up close (this is as close as I could get thanks to private property issues), you can see a nice shot of it in Bjornstads book. Look on page 110 of his book, "On the Trail of the Ice Age Floods"
This boulder is just a few miles from where I lived in Kennewick and I tried several ways to get to it, none successful to this point. I'll be back to try again