Giant Dire Wolf Skin & Giant Polar Bear Skin
These two items are both farmed from the same location in Permafrost Keep and share a use in creating Unfired Poison Vials. In order to reach 350 in Pottery you'll need to farm up at least three of these two pelts since they are used in three different recipes each.
In order to find the enemies that drop these items in Permafrost Keep you'll need to travel to the northern portion of the zone and past the ice giants. On your way to Vox you'll need to fall down into the 'pit trap' and this is where you'll find the wolves and polar bears that we need to defeat. This location is circled on my map.
3 Giant Dire Wolf Skin
3 Giant Polar Bear Skin