1909.] NATURAL SCIENCES OF PHILADELPHIA. 385 



Ammophila arenaria (A) and Solidago sempervirens on the other, 

 while a thicket where Rhus radicans is prominent occurs on the higher 

 sand slopes (Fig. 4). The water of this lagoon, although it is near the 

 center of the island, remains salt, because at high tides it is replenished 

 by the entrance of sea water, which enters through a valley-like depres- 

 sion running diagonally across the island. 



Salt Marshes along Shark River. 



Shark River (Fig. 5) rises inland about seven miles from the coast. 

 The inner line of its watershed is marked approximately by the New 

 Jersey Southern Railroad, running between Farmingdale and Pine 

 Brook near Eatontown. It runs seaward in two main branches, fork- 

 ing from each other close to Shark River Bay. The southern branch 

 rises in elevated country (100-164 feet contour) near Shark River 

 Station on the New Jersey Southern Railroad. The northern branch 

 rises near Centerville, and flows approximately southeast to join the 

 other branch before they enter Shark River Bay, which is fresh at 

 its head, but gradually becomes more salt near its narrow outlet to 

 the sea, more or less surrounded by salt marshes or salt marsh islands 

 (Fig. 5). The bay is about two miles long from east to west. The 

 outlet is marked by the line of the New York & Long Branch Rail- 

 road, which crosses by a trestle bridge. Below the trestle the river 

 channel is scoured by the rapidly moving inflowing and outflowing 

 tides, and its banks are lined with salt marshes now to be described. 

 The close proximity of these marshes to Belmar enabled me to visit 

 them frequently on foot and in a boat, and to construct a map which 

 represents the distribution of the salt marsh plants (Fig. 5). 



The salt marsh vegetation of the south shore of the river, between 

 the ocean and the trolley bridge, will be described in detail first. The 

 river channel (sp. gr. 1.0212) is fringed by Spartina stricta maritima 

 (X) where the muddy shore is submerged at high tide (sp. gr. 1.0140). 

 This grass also fringes the marsh island, which was originally formed 

 by tidal action. Near the ocean front Spartina patens (V) forms a 

 strip which is barely touched by salt water at high tide, while in differ- 

 ent association and on the same level is found Scirpus pungens (Z) 

 associated with Limonium carolinianum (A). These plants are backed 

 by low dunes covered with Triodia cuprea, Ammophila arenaria } 

 Strophostylcs helvola, Lathyrus maritimus, Euphorbia poly go ni folia, 

 Cakile edentula, Cassia nictitans, Ampelopsis quinque folia, Solidago 

 sempervirens, Trifolium repens, T. hybridum and Xanthium echinatum. 

 In the bend of the river between B Street and D Street, Belmar, the 

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