sentences:  The canal development of North and South Yunderup is situated several kilometres upstream from the estuary.The first European exploration of the area was in July 1829 when a group, led by Captain Currie of and accompanied by botanist James Drummond, marched a short distance inland from present day Rockingham and after climbing a small hill at what is now Baldivis, sighted a river in the distance.This was later named the Serpentine River, which is to the north of the Murray and for some time was confused with the Murray, which was not encountered until later that year.