Do these two parts in Hurley's logic book introduce natural deduction or different deductive systems?

Question

In Hurley's An Concise Introduction to Logic

• Section 6.6 Arguments Forms and Fallacies introduces several valid argument forms: modus ponens, disjuctive syllogism, ...

• Ch 7: Natural Deduction in Propositional Logic introduces rules of inference which "should be familiar from Section 6.6".

Does Section 6.6 also introduces natural deduction, or a different deductive system (like Hilbert deduction)?

If both Section 6.6 and Chapter 7 introduce natural deduction, what is the difference between them? (Apart from subjective writing plan of the author.)

Thanks.