Conversation so far:
When did the Byrds form?
In early 1964 they began to assemble a band that would become the Byrds.
Who were the original members?
fellow folkie and Beatles convert Jim (later Roger) McGuinn.
Anybody else?
David Crosby and became the tambourine and harmonica player.
Bassist Chris Hillman.

Question: What was his role in the band?
Self-contained rewrite: What was Clark's role in the Byrds?