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. The prevailing winds are from the west and northwest. New Jersey is in the track of storms, which cross the continent from the west. The south and east winds blowing from the ocean toward the storm centers bring with them much moisture and insure the state an ample rainfall. Local showers or thunderstorms which move from the west or northwest are frequent in the spring and summer months. In the summer time all along the coast the benefit of sea breezes is felt (Sec. 372). The rainfall is sufficient for all kinds of crops which can be grown in the state. It is greatest in the northeastern part of the state, where the annual precipitation is more than fifty inches; and least in the southern and southwestern part along Delaware Bay, where it is about forty-one inches. [Illustration: Sandy Hook from the Highland Light] [Illustration: Drainage basins in New Jersey] DRAINAGE