describe the great river and whwt they saw

This chapter recounts ten days of travel along the Anduin River. The first few days are peaceful but one night, Sam spots a log in the water that seems rather ominous. There are two eyes shining in the murk and it does not take long to confirm that this is Gollum. After escaping from custody (quite a few chapters ago), Gollum began tracking the group once they left the caves of Moria. When the company reaches the challenging rapids of Sarn Gebir, they discover themselves in an ambush, with arrows flying overhead and an abundance of orcs. An incredible shadowy shape rises from the east and speeds towards the ship, churning up the evil groans of its compatriots, as it glides upon the water. Legolas shoots a perfectly aimed arrow into the creature, felling it. After this, they hear sounds of mourning and while Frodo has a good suspicion regarding this creature's identity, it remains unsaid. After the rapids, the company continues to Amon Hen at the river's end.