Inside is a natural bridge over a very deep chasm. On the other side of the bridge are some Frost Trolls (×2). There is also a copy of the skill book Mystery of Talara, v3 there.
If the Dragonborn is brave, a jump off the bridge and into the pool of water at the bottom of the chasm can be survived. Underwater, there is a chest (~100 value (L54)) and a Grand Soul Gem, as well as an entrance to the lower part of the cave. This passage leads to an exit known as Lower Steepfall Burrow.