LONG ISLAND XEfiETATFON 



197 



greatest where the slope is small and the rocks extend farthest into 

 the Sound. 



Returning to the conditions at Eatons Neck J.ight it should be 

 noted that as we approach the shore or the low tide line on the 

 rocks there is a marked increase in the areas occupied by Fucus, 

 Ascophijllum , Enterovwrpha, Edocarpus, etc. These belong to 

 the Rockweed Formation. The transition between these forma- 

 tions is very gradual, and one misses entirely the well definined 

 line of separation so frequently seen on land. 



PROTECTED SUBMERGED BEACH 



The Eel Grass Formation. Within the harbors are consider- 

 able areas in which the wa\'e action is so slight that only the finer 

 drift particles are moved. These become places of aggradation. 

 The upbuilding is usually slow and the bottom is made up of sand 

 and mud. These are typical places for the growth of eel grass. 

 This plant spreads by rootstalks and usually forms a compact 

 growth. With its long upright ribbon-like leaves it produces the 

 appearance of a submerged meadow. Ruppia maritima is com- 

 monly associated with it. The conspicuous secondary species are 

 epiphytes on the eel grass and include Cem/riiwm rubrum, C. stridum, 

 and Melosira granulata. Ulva laduca,Enteromorpha dathrata, and 

 E. intestinalis are also of secondary importance. In Great South 

 Bay on the south side of Long Island this formation occupies ex- 

 tensive areas in water whose depth is about a meter at low tide. 

 There it not only grows to greater length but the number and 

 variety of associated algae is very much increased. As an aid to 

 aggradation it is of the greatest importance, not only because of 

 its own contribution of vegetable matter but because of its effi- 

 ciency in slowing down waves and currents and causing them to 

 deposit any materials held in suspension. Where this formation 

 attains its greatest development, owing to stagnation, the water 

 is warmer than elsewhere during the summer. Not uncommonly 

 this formation is associated with a salt marsh and later passes into 

 that stage of the vegetation. 



In tidal creeks, such as that on the east side of Center Island or 

 the north side of Lloyds Neck, the Eel Grass Formation is domi- 



