One of many small islands strung out along the south side of Rock Harbor, Tookers has some nice exposures of lava flow tops on its south side. Flow tops are amygdaloidal and less resistent to weathering. Flow interiors are massive and featureless, except they nearly always have at least rude columns.
Boreal Research Center, Davidson Island
On this island is the Boreal Research Center, a residence for researchers at Isle Royale. After stopping at the dock in front of the center, we will walk around this small island, visiting another exposure of the epiclastic sedimentary rocks and an exposure of a columnar jointed, ophitic flow on the SE comer of the island. The wave-washed shoreline has exposed a surface perpendicular to the columns, which are 2-3 m (6-10 ft.) across. We will see many exposures of large columns like these in the next few days, as they seem to be a regular feature of ophitic flows at Isle Royale.
