If you are using the pagination with basic reloading then it will automatically crawl by Search Engines(Then it should have different urls for each page).

When you are using Ajax to load more content to the same page then above case will not work, but you can use an alternatives like dynamically change the url with ajax( without # append to the url bcoz when you append # to the url , after the # will not crawl the Search engines).

You can achieve it with [history.js][1]  jQuery library it will work only with HTML 5 supported browsers ie, In Ie its append # symbol. 

By using this method you will get different urls for each page then search engine will index your page content.

Hope its make sense..


  [1]: https://github.com/browserstate/history.js/