Pebble Beach lies in a cove just west of the Split Rock Lighthouse. The pebble part of the beach is limited to the western end of the little bay and the pebbles run out in both directions. On the south side, the tombolo looks like it has barely enough gravel to reach its island (see aerial below). And on the north side, captured in one of these photos, the pebbles transition abruptly to a sediment-starved beach. The local bedrock is sufficiently resistant so that it may provide little new material to the beach and the beach is left with whatever the glaciers and any local streams originally left it.