jack and ralph are like "two continents of experience and feeling, unable to communicate." describe the nature of the conflict between the two
I like the "order versus chaos" analogy above. The two boys are opposites in their inclinations (after the book picks up speed). Yet, at first the two of them are friends. They have an affection for one another and each wants to be liked by the other. They seek one another's respect. Coexistence is not going to be possible however, not in the long-run. Ralph and Jack each want to be the leader and they both seem to think there can be only one leader or chief - power cannot be shared.
You have some great analysis so far. This is one of my favorite images in the novel. Jack and Ralph, the two continents, are equal in stature and position, at least early on. Each of them has their following and both of them have some initial conflicts with that group. Their first expedition up the mountain is a time when they are able to work together; however, when they see the candlebud bush the differences between them are manifested. Ralph looks at them and sees that the flowers look like candles but they cannot be lit and are therefore useless to them. When Jack looks at them, he quickly and brutally slashes them, dismissing their usefulness to them because they cannot be eaten. There it is--both boys are pragmatists, but one is cruel and leans toward savagery even when it is a harmless plant.
The conflict between the two is like order versus chaos. They both want to be in charge, but Jack wants to control every aspect of things and basically do whatever he wants. Since Jack is not stable by the end, this leads to chaos. Ralph, on the other hand, wants to continue the decency of society and keep things civil.
Jack and Ralph as alike as they are different. Ralph and Jack are both independent, powerful boys, with the capabilities to be great leaders. However, like "two continents separated from each other", they find it difficult to see eye to eye and understand each other. The nature of their conflict is rooted deeply in how they feel a leader should conduct himself. Jack feels a leader rules by fear and intimidation. There's a superior leader who is all-knowing and then there's everyone else below him who must hang on his every word. A dictatorship is what Jack views as leadership. Ralph, on the other hand, sees leadership as a democracy. He feels that you rule by giving the others a voice and letting them contribute to the decision-making process. He doesn't feel that an effective leader has to make the others fearful of him.