1940 Census Map Showing Developed Island in Hewlett Bay in Oceanside

This is taken from the 1940 US Census maps and it shows the island of what is now East Meadow (not the town) the island in Hog Island Channel in Oceanside that appears to be developed with a road circling it called The Prado and I'm wondering if this ever was developed or what this map is showing. Its a Hagstrom map so it should be accurate, I'd think

http://1940census.archives.gov/search/?search.census_year=1940&search.city&search.county=Nassau+County&search.page=1&search.result_type=map&search.state=NY&search.street#city=&filename=m-a3378-00041-00607.tif&type=map&county=nassau-county&state=NY&index=13&pages=18&bm_all_text=Bookmark&searchby=location&searchmode=browse&year=1940