Shadowgreen Cavern

Shadowgreen Cavern is a cave in the north of Skyrim near the Imperial city of Solitude. Inside are Wolves, Spriggans, and Cave Bears.

Walkthrough
There is a path circling up to the top the giant rock in the center of the cave with some Spriggans and Cave Bears guarding a boss chest containing Noster's Helmet (if you are on the retrieval quest) and some random loot.

After the little dip in the landscape, you'll fight a Spriggan who enlists the aid of a Cave Bear to help her fight. You'll encounter a Spriggan Matron, and another Spriggan. After finishing them, just a little beyond before the spiral path, there is a Corundum Ore vein on the right.

Behind the chest with Noster's Helmet in it, there is a path extending over a gorge. Down and to the right of this path is a protrusion of land with another boss chest (expert) covered by plants. To reach the chest you will need to use the Whirlwind Sprint shout from the top of the hill (can actually be reached without it). After looting it you can carefully move along the ledge till you are near the edge where the pond below is visible. There is a ledge under this land protrusion with a skeleton that has a coin purse and helmet near him. Use the Whirlwind Sprint shout once again and you should be able to reach the water without falling to your death. To the left of the path there is an easily accessed chest, and directly below that a piece of land with a Moonstone Ore deposit. To get to the area with the Moonstone Ore deposit, you have to drop down.

Loot

 * Meridia's Beacon (chance of it being located here).
 * Noster's Helmet (chance of it being located here).
 * Moonstone Ore Vein, reached by crossing the arch at the top of the spire and dropping down to it. A skeleton with items lies next to it.

The 1st chest (apprentice) is buried in a tree stump on a ledge above the stream source to the East. 2nd chest is on the island at top of spire; 3rd chest on a ledge accessible by the stone bridge. The 4th chest (Expert) is on a ledge due North from the small island at the top of the spire. You can reach it by using Whirlwind Sprint to leap across the chasm gap, taking some damage hitting the cliff wall.
 * Corundum Ore Vein
 * Various alchemy ingredients; Blue Butterfly Wing, Taproot, Bear Claws etc.
 * 2 Chests
 * Chest (Locked: Apprentice)
 * Chest (Locked: Adept)
 * Iron Greatsword and an Orcish Shield (at the bottom of the small, steaming pond with the mammoth remains in it)
 * Glass greatsword, at bottom of pond to left of entrance
 * Note:
 * Flawless Diamond, in chest near the first Wolf encountered.
 * There is a Coin Purse at the bottom of the pond next to a Skeleton along with random loot, as well as a Potion of Healing.

Location
Shadowgreen Cavern's icon and quest markers on the map can make its location confusing. It is shown to be near the middle of the mountain region near Solitude, east of the Thalmor Embassy, and the quest markers seem to in random spots circling the Thalmor Embassy (I've read about some being on the Embassy, while mine was just slightly northwest of the embassy). The entrance is actually on sea-level. If you find it hard to ride a horse down the mountain, you can also reach it from the northern side. It takes a bit longer, but if you've discovered Broken Oar Grotto, or even Brinewater Grotto or the Solitude Lighthouse, you should be able to go northwest along the water until you are past the mountain Broken Oar Grotto is on. Then, you should be able to go southwest to the cavern entrance.