In The Great Gatsby, where can I find a text passage that shows the contrast between East Egg and West Egg? Would Gatsby's party be an example?
Gatsby's party in Chapter 3 would be an excellent example, although the majority of the chapter concerns the drunken behavior of those from West Egg and New York. Nick does comment, however, on Jordan Baker's companions from East Egg. These people stick together, sharing a common snobbishness, as they observe the excess and outrageous behavior swirling around them:
Instead of rambling this party had preserved a dignified homogeneity, and assumed to itself the function of representing the staid nobility of the countryside--East Egg condescending to West Egg, and carefully on guard against its spectroscopic gayety.
After sitting with "her people" for a little while, Jordan finds them boring and asks Nick to leave with her: "This is much too polite for me."
In Chapter 4, Nick recounts the names of some of the people who came to Gatsby's house that summer. This is Fitzgerald's using the catalog technique to develop the contrast between the people of East Egg and those of West Egg. The people from East Egg have traditional, Anglo-Saxon names, the kind of names that suggest people who attended the best Eastern schools and moved in the highest circles of American society. These are the names of families that have deep roots in the East. The people from West Egg have ethnic-sounding names, suggesting a much more recent immigrant heritage. Some have scandalous pasts. Some engage in shady businesses. Some are "show people," surely a group the East Eggers would disdain.
By way of example, Dr. Webster Civet came from East Egg; James B. ("Rot-gut") Ferret (clearly a bootlegger) lived in West Egg.