What are the advantages of using Javascript-only versus using JQuery-only?

I have limited experience with JavaScript and JQuery coding. I've added bits and snippets of each to HTML pages but I've mostly coded server-side stuff in other languages. I've noticed that while you can theoretically do the same things using either of the two approaches (and of course you can even mix 'em up in the same project) there seems to be a tendency to always start using JQuery from the very beginning no-matter what the project demands are.

So I'm simply wondering, are there any punctual benefits to not use JQuery-only but instead to just use plain old JavaScript?

I know this looks like a non-question because it can be said about it that "there's no definite answer" or "it can be debated for ever", but I'm actually hoping for punctual answers such as "You can do this in one approach and you cannot do it with the other".

==EDIT==

As per scrwtp's comment, I'm not referring just to the DOM Handling part. My question is rather: JQuery is a library. For Javascript. What I find strange about this library as opposed to other libraries for other languages is that in JQyery's case it seems to be designed to be able to use it exclusively and not need to touch Javascript directly. This is as opposed to let's say Hibernate and SQL, where even though the library (or rather framework in this case, but I think the analogy still applies) takes the handle on A LOT of aspects, you still get to use SQL when using it, at least for some fringe cases. However in JQuery & Javascript case, you could do anything you do with Javascript using only JQuery (or at least that's how it seems to me).