i8oi 



The central plain has few surface features to produce mos- 

 quito-breeding places. Moreover the soil is very porous and 

 there is in consequence little permanent surface water in any 

 form. Its problems are derived largely from the regions to the 

 south. 



SOUTH SHORE SAIvT-MARSH PROBLEM. 



The salt-marsh problem on the south shore is by far the most 

 important problem and will be considered first. 



From Rockaway Inlet eastward a narrow strip of barrier 

 beach and sand dunes parallels the south shore of the main- 

 land of Ivong Island for most of its length. This beach lies 

 at an average of some three or four miles off the main shore. 

 The waters between these beaches and the mainland are divided 

 by projections into various shallow sounds or "bays." The 

 westernmost of these is Jamaica Bay, most of which belongs in 

 New York City. The Rockaway Peninsula separates Jamaica 

 and Hempstead Bays. Near the eastern boundary of Nassau 

 County Hempstead Bay becomes narrow and gives way to South 

 Oyster Bay, which in its turn opens into Great South Bay. 



Into these shallow and comparatively quiet waters have 

 pushed the marine growths which form salt marshes. The 

 growth has been along three lines — first, outward from the main^ 

 land; second, inward behind the barrier beaches; third, the 

 formation of islands by the growth of vegetation over shallows 

 and the accretions of inorganic material left by the tides. In 

 Hempstead Bay the development of the salt marsh has pro- 

 ceeded so far that more than half the original water surface of 

 the bay is now salt meadow or tidal flat, most of it being well 

 developed marsh. 



The outer beach marsh is built up on sand flats and is not 

 severe breeding territory, but, as has already been mentioned, 

 offers some obstacles to the use of ordinary ditching methods. 



The mainland marsh follows the coast in a continuous strip, 

 about a half mile wide, clear across the county. The inner 

 portion of it is a hay meadow occasionally giving way to a more 

 or less brackish fresh marsh. The outer portion is low, but 



