A coastal plain is defined as a low relief region of largely undisturbed sedimentary strata that dips gently in the seaward direction. Coastal plains commonly have well-developed drainage systems, some that are influenced by adjacent major mountain ranges and others that are not. Along the Gulf Coast,this type of coastal plain is generally present throughout, except for the Mississippi Embayment where the Mississippi Delta occurs. In the delta there is a major landward extension of coastal plain strata that has accumulated on a subsiding, gently sloping trough. On the East coast, the coastal plain is similar in nature to that found in the Gulf provinces. It begins in south Florida and terminates near the mouth of the Hudson River.