Reclaiming your Shovel & Finding a path to Turtle Rock
From the entrance of Eagle's Tower you'll want to travel back to Mabe Village and head over to the beach, enter the building in the center and speak with Goriya to purchase your Shovel back for 300 Rupees. now equip your Ocarina and teleport over to Tal Tal Heights then make your way up to the top of the Mountain where you'll find a small hut, head slightly left and throw a Bomb down into the hole below, causing a Secret Seashell to be fired out.
Once you've picked up the seashell head across the bridge on the right and remove the stones to find another Secret Seashell then go back to the left and hop over the bridge to find Marin stuck, equip your Hookshot and pull yourself across to the left grabing Marin along the way. After the cutscene has ended the Owl will approach you with some information on where to find Turtle Rock.
Head south and down the stairs, continue to follow the path left and proceed down another set of stairs, Hookshot your way across the hole and exit the cave, now slowly make your way to the top of the Mountain whilst watching out for the falling rocks.
Upon reaching the top you'll want to remove the stones in the top right to find a Secret Seashell then open the Chest to the left for 50 Rupees, now remove the stone below the Chest and head down the stairs, pour the Magic Powder into the center to gain the ability to hold extra Arrows. Exit the cave and proceed left, drop down and place a Bomb against the crumbling wall and head through, use your Shield to push back the flames and go left up the stairs.
Use your Shovel to dig up a hole to find a Secret Seashell then head left to find a statue, play the Ballad of the Wind Fish in front of it to bring it to life, now you'll need to defeat the enemy to gain access to Turtle Rock. In order to defeat the statue you'll need to wait for it to charge at you and dodge out of the way causing it to become stunned, place a Bomb near it's head and repeat.
After a few blows to the head you'll be able to hit him with your Sword, once the enemy has been defeated the Turtle Rock will be accessible.