Formation of River Features

In class at the moment, we are studying the different features that you find in the upper, middle and lower courses of a river. I have found some simple animations showing the formations of some of these features. For waterfalls, click here, here for ox bow lakes, and here for v-shaped valleys and interlocking spurs. There is also a powerpoint presentation that I found on the internet here, that talks about some different river formations. Here is a good wikipedia page on waterfalls. There also some good articles about other river features on wikipedia if you search for them.