Speak with Hamuul Runetotem.
The shells you brought me have a taint, one I have never before seen. I am certain the water of the Oases is the cause, and I can sense the confusion they cause this land. It is as if the land dreams and cannot awake.
The Wailing Caverns must be the source of the taint. But before you go there, speak with Hamuul Runetotem, the elder druid. I sent word to him of the happenings in the Barrens. He is wise, and can offer you counsel.
You will find him in Thunder Bluff, on the Elder Rise.