Conversation so far:
Where was Mitchell's first expedition?
Mitchell formed an expedition consisting of himself, assistant surveyor George Boyle White and 15 convicts who were promised remission for good conduct.
Where did they go on their first expedition?
On reaching Wollombi in the Hunter Valley, the local assistant surveyor, Heneage Finch, expressed a desire to join the expedition.

Question: What was Thomas Mitchell's goal for the first expedition?
Self-contained rewrite: What was Thomas Mitchell's goal for the first expedition?