Due to erosion and differences in forms of measurement, it is contested that Cape Blanco in southern Oregon is the westernmost point in the contiguous 48 states. Its claim as the westernmost point is also disputed because during high tide, Cape Alava is just as far west as nearby Cape Flattery.
In early 1834, a Japanese ship, the Hojun Maru, made landfall at Cape Alava after a 14-month drift on the Pacific Ocean. It was supposed to bring rice to Edo, but was then carried away by a storm. At the time of arrival at Cape Alava, only three of its crew were alive. They were then looked after and briefly enslaved by Makah; see the Otokichi article for more information on this.
The rich mixture is a result of the combined erosive power of the ocean and relatively recent glacial activity. According to the Washington State Department of Natural Resources, the area's sediments are classified as Unconsolidated Deposition, translating to the geological equivalent of a grab bag. More finely, the deposits are listed as “Quaternary Sediments, Dominantly Glacial Drift, includes alluvium”. The Quaternary time period dates to the end of the most recent ice age, roughly 10,000 to 14,000 BCE. A geologic map of Washington shows the unique nature of such sediments being exposed to the full grinding force of the Pacific Ocean. There are many such areas scattered about the Puget Sound, yet very few areas on the unprotected Washington coast.