Trapped

Wings of Fire meets Jurassic Park in The Deadlands: Trapped, the second book of this action-adventure series by Skye Melki-Wegner about five outcasts—and former enemies—who are the only hope to save their warring kingdoms from impending doom.
As bloody battle rages on between the two surviving dinosaur kingdoms, Eleri and his fellow outcasts, newly exiled from their herds, are searching for evidence to prove a mass conspiracy—a conniving cabal of carnivores have manipulated the herbivore kingdoms into war, so they can feast on the slain. But after their temporary home is discovered by a vengeful pack of raptors, the exiles must flee and soon find themselves trapped inside the Fire Peak: the volcanic heart of the dreaded Carrion Kingdom.
Before they have a chance to escape, they discover a cavern of imprisoned herbivores, who are being picked apart—literally—one by one. Can the outcasts stage an elaborate heist to free the prisoners and gather proof of the Carrion Kingdom's vicious plans in one fell swoop?