Consider the following statements:

1. The western coastal plains are narrowest in their middle section and broaden towards the north and south.
2. Rivers crossing the western coastal plains generally do not form deltas.
3. The eastern coastal plain is broader and contains well-developed deltas formed by major east-flowing rivers.
4. The eastern coast possesses more natural ports because its continental shelf extends far into the sea.

Which of the statements given above are correct?