Brooks shot a 67 at Spyglass Hill.
Duval was not as fortunate, falling to two under par after today's disappointing 76 at Spyglass Hill.
Spyglass Hill is the third course used in this pro-am.
Spyglass Hill and Poppy Hills golf courses also have restaurants open to the public.
With a two-under-par 70 at Spyglass Hill today, Jones moved into first place with a 10-under 206.
Tom Kite was another 2 strokes back after shooting a 70 at Spyglass Hill.
The third course used for this tournament is Spyglass Hill.
All the holes at Spyglass Hill were later also named after characters and places from Treasure Island.
The sun was still hidden behind Spyglass Hill, which came down to the sea in dangerous cliffs on this side of the island.
We landed the boats at the mouth of the second river, then began to climb Spyglass Hill.