Coal can be both land based and marine. Most of the coal in the Sydney basin is marine based as a result of the Sydney basin which was a delta stretching from around Port Stephens, into Lithgow and down as far around Nowra. It also protrudes further out into the ocean off Sydney. These coal deposits are a result of massive quantities of marine life that became buried from the silting up of this extensive area (known as the Sydney Basin). It all started some 190 million years ago. There are huge deposits of high quality coal as a legacy contained within this basin.
