Ok so here is the answer to your question:
In the Tolkien mythology there are different kinds of trolls mentioned. The "stone trolls" (Trolls that turn to stone in the daylight) are only mentioned in "The Hobbit".
There are also Mountain Trolls and Hill trolls. You may remember the mountain trolls manning "Grond" the giant battering ram at the battle of Pelenor Fields. The hill trolls were used during the war of the ring by Sauron as well. They were the big guys with the large hammers.
hope this helps.
