Barnegat lighthouse>
The fourth zone, the Coastal Plain, includes the remainder of the state south and east of the Fall Line. The land of this zone is highest in the interior along a range of elevations extending from Atlantic Highlands in the northeast to Mount Holly in the southwest, and slopes outward from these elevations towards the margins of the zone. The greatest elevation is 390 feet, which is found in Monmouth County. About three fourths of this portion of the state has an elevation of less than 100 feet and about one third has an elevation of less than 50 feet. The Coastal Plain is bordered along Delaware Bay and the Atlantic Coast by salt marshes, or tidal marshes, often called salt meadows, whose elevation above sea level is rarely as much as four feet. The total area of these marshes, including those of the valley of the Hackensack River, is almost 660 square miles. Along the Atlantic coast the marshes are separated from the ocean by beaches. These are low ridges of sand, constructed in the shallow water by the action of the waves and wind. These beaches are absent along the shore of Delaware Bay and along the coast from Manasquan to Monmouth Beach. The water between the beaches and the mainland is shallow and is becoming more shallow because of the deposit of sediment which is washed down from the land by streams.
Although the coast line of the state along the Atlantic is 120 miles long, there are no good harbors on this line, because of the barrier beaches and the shallowness of the water between the beaches and the mainland.
Lake Drive, Greenwood Lake
The northern fourth of New Jersey was covered by ice during the Glacial Period (Sec. 32). It therefore contains many moraines, or deposits of material carried along by the glacier. These deposits consist of clay, sand, gravel, and bowlders. In some places they take the form of hills or ridges, in others they are spread out as level sheets. Some valleys are partly filled by them. Many lakes in the northern part of the state occupy basins which were scooped out by the glacier, or were formed from river valleys whose outlets were blocked by glacial deposits. The terminal moraine which marks the southern limit of the glacier extends from Belvidere, through Morristown, to Perth Amboy. As the ice passed over the hard rocks of the mountains it polished their surfaces, and left in them scratches, which indicate the general southward movement of the glacier.
The Coastal Plain was once beneath the ocean and was part of the continental shelf which extends along the Atlantic. The ancient shore is now the Fall Line.
CLIMATE
The climate of New Jersey is milder and less subject to extreme fluctuation than that of the interior states in the same latitude, because it extends along the ocean (Sec. 107). The average annual temperature of New Jersey is 51.5°. The average annual temperature of the extreme northern part is 5° lower than that of the extreme southern end of the state. The lower temperature of the northern part of the state is due to the higher latitude, its distance from the ocean, and its greater altitude.