Possible Buddhist School Lineage

I've been reading a textbook I have on the history of religion, as well as a number of Buddhist websites and Wikipedia articles, trying to understand the historic relationships between the various Buddhist schools. I made this chart in an effort to work out what I was reading (click on it to enlarge, then hit your 'back' button to return). However, I have no idea how accurate it is, so please take it with a grain of salt. I am also posting a reference to this page on the www.comparative-religion.com forums (in the Buddhist forum of course). Click here to see that forum page. Hopefully folks there can tell me if my chart is accurate. If not, I'll probably correct by editing this post.

Edit, January 20, 2006: I did receive good input from both the comparative religion forum, as well as ilovephilosophy.com, which can be seen here. The picture now on this entry is an updated one from the original which it replaced (based on that input).