Filters tag city state Photos tagged gulf islands national seashore gulf islands national seashore The building was formerly used as the Coast Guard Station. The beach road bisects Santa Rosa Island. The dunes form undulating ridges along the north side of the beach road. This area is across the road from Parking Lot 10 at the Gulf Islands National Seashore. Sparse vegetation holds the dunes in place. Some of dune formations on the north side of the beach road rise to a height of about 30 feet. The Gulf can be seen on the far right of the photograph. Beach grasses have long roots that form a subsurface net, keeping the dunes from disintegrating. Beach elder accumulates sand rapidly and produces low rounded dunes. Beach elder (Iva imbricata) has sparse, woody, upright stems and fleshy narrow bright green leaves. Small lavender flowers occur in late summer.