Tramp Harbor, Vashon Island This beach is located on the north
side of the isthmus that connects Maury and Vashon islands. It
is not located in a park as are the other beaches surveyed, but
it is heavily used. The area is now known as Portage. The beach
is relatively flat and is cobbled down to about the +4' foot
tide level. It is composed of sand and gravel below that. The
eastern end of the survey area lies at the foot of a clay bluff.
There, the substrate is quite sandy and the presence of buried
wood bearing ax marks is evidence of relatively recent slides.
The beach does not show the effects of heavy surf. Perhaps that
absence explains the large numbers of sand dollars. There were
23 species of invertebrates identified on this beach which
placed it second lowest in diversity. Most of the animals noted
were mollusks (18 of the 23 species). Eleven (11) of the
mollusks were bivalves, four were limpets and three were
chitons. It must be noted that the survey here was less complete
than at most beaches becaus