This relates to the following sentence in the Wikipedia article on Moses Coulee:
“The mouth of Moses Coulee discharges into the Columbia River at the Great Gravel Bar of Moses Coulee, a National Natural Landmark which was designated a landmark because it is one the largest examples of bars created by outburst floods of Lake Missoula over the Channeled Scablands of Washington.”
The geologic history of the coulee and of the bar at its mouth is relatively complex, but the site of the NNL designation is definitely mis-located in the Wikipedia article, and perhaps also in other sources you may have seen.
The Great Gravel Bar of Moses Coulee that has been designated a National Natural Landmark is not the bar located at the mouth of Moses Coulee. The designated bar is about thirty miles to the northeast, on the west side of the coulee, and is crossed by Highway 2.
You may want to confirm this with Steve Gibbons, regional coordinator for the NPS National Landmarks Program, at firstname.lastname@example.org or 360-854-7203.
An additional and significant bibliographic reference related to Moses Coulee is this dissertation:
Larry G. Hanson, The Origin and Development of Moses Coulee and Other Scabland Features of the Waterville Plateau, Washington, Ph.D. dissertation, University of Washington, 1970.
Unfortunately the author is deceased.
Dale Middleton 21:56, 15 October 2007 (UTC)