The morpho-sedimentary units within the estuary are related to the geomorphological evolution of the barrier spit as it migrated inland and extended southerly (Psuty, 2004).
The dominant sedimentary feature is the broad zone of medium sand that forms a 2-3 km wide shelf extending westerly from the barrier spit into the bay.
Former flood-tide delta forms compose the broad shelf along the estuarine margin of the barrier spit, and subsequent reworking of the tidal delta d~ posits has altered most of their channel morphologies.
As with other lagoon-type estuaries, the distribution and makeup of the morpho-sedimentary units within the embayment are related to the geomorphological evolution of the ancestral barrier spit as it migrated inland and extended westerly (Bokuniewicz and Schubel, 1991).
Kelly's Island (46[degrees] 50' N, 64[degrees] 55' W), 2 ha in size, is part of a 26-km crescent of barrier spits
and islands that separate Kouchibouguac Bay of the Northumberland Strait from the shallow estuary-lagoon system of Kouchibouguac National Park (Beach 1988).