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.
What was his role in the band?
Clark wrote or co-wrote many of the Byrds' best-known originals.
What songs were those?
"I'll Feel a Whole Lot Better", "Set You Free This Time", "Here Without You", .
Were there more songs he wrote during this time?
", "You Won't Have to Cry", "If You're Gone", "The World Turns All Around Her", "She Don't Care About Time" and "Eight Miles High".

Question: Did he play any instruments?
Self-contained rewrite: Did Clark play any instruments in the Byrds?