Creeks were typically sampled at a confluence and then up the corresponding two branches, labeled by distance from the confluence and yellow (Y) or blue (B) corresponding to the flagging tape used on site markers; for example, a site 100 m upstream from the confluence on Clubhead Creek would be designated Clubhead B100 or Y100. Distance up the creek was determined by stakes laid out in 50 meter intervals. Sampling was conducted at or near low tide as much as possible. At each site, the sampling transect would start at the edge of the Spartina patens zone, and continue down the creek bank until reaching the center of a drained creek or until reaching water. Quadrats were laid out by deploying a ladder-like template: 1 meter wide by 2 meter long, divided into sections at 25cm increments. This ladder would be repeatedly laid across the creek bank to cover the entire transect from S. patens to the creek center. Each section of the ladder would enclose an area of 0.25 m2 in which all mussels (Geukensia sp) and snails, Ilyanassa sp. and Littorina littoria. Notes on zonations (eg. Beginning and end of S. alterniflora zone), and surface features, as well as presence of other large organisms (eg. Oysters or other snails) were noted. NOTES AND COMMENTS: Sampling site locations were either: At the confluence of two tidal creek branches. Y or B followed by a number referring to meters upstream from the Confluence for those creeks with paired branches. A number, referring to meters upstream of an area in a creek without paired branches which is equivalent to the confluence of branched creeks. D100, referring to 100 meters downstream of the confluence or equivalent Zone: refers to the increment along the sampling ladder where organisms were counted.