In Lord of the Flies, chapter 6, how do Ralph and Jack differ in their actions as they climb the new hill?

In chapter 6, Jack and Ralph and a few others discover
Castle Rock, the coral and rock island on which Jack and his followers decide to make
their fortress.  Castle Rock is high and separate from the surrounding land.  It
overlooks one end of the island.  The approach, which is a rock bridge, is precarious
and Jack hesitates to cross it, so Ralph goes first and Jack soon joins him.  Ralph sees
the island for what it lacks - natural resources that will benefit them in surviving
life on the island.  He notes that there is no fresh water, no shelter, and no food. 
Ralph says it is "...a rotten place." He does not see any potential for the mass of rock
and coral.  Jack, however, sees that the island would be ideal for a fort.  He sees how
easy it would be to defend the island since it has only one main access point and from
the top of it, Jack can see all the way around it.  Ralph sees the island for its
usefulness in helping them survive peacefully, Jack sees it for its usefulness in
helping him gain power and control.