In Pre-Searing you will also find some Devourer nests here. You lack the necessary knowledge to extract the Eggs from the clutch though. You need the help of an Egg Hunter to get your hands on an egg.
Starting from Ascalon City, cross the river (the dry river bed respectively). The cave is under the large hill on the south-east side of the river. The entrance to the cave is on the south-east side of the hill.
The following quests take you to the cave: