This used to be a log landing, where timber was collected before being rafted to pulp mills, but it has now been wonderfully stewarded back into health.
UMD - Restoration
North Shore Stewardship Association
I'm sure the industrial history impacted the site topographically geologically and biologically, but I felt I could still sort out some of the beach's story from our short visit.
A rocky point, once an island, anchors the tombolo. The point reportedly consists of thin-bedded lavas (very old ones), covered with lichen, and visitors were encouraged to avoid damaging the latter.
The beach in the cove - an east-facing pocket again - is a mix of boulders, cobbles, and gravel, with the beach coarsening out towards the point. Some of this may be the inherent sorting one often finds on pocket beaches, but the cobble at the outer end was awfully large for the protected bay. I suspect that it may be overwash from the coarser grained beach on the exposed side of the tombolo.