Me Treasure! (Part One)

Three treasures and a map I buried today,
Here are the hints to show you the way.

The map is hidden in a heirloom ring,
It contains an ancient six cornered thing.

At the 50 mile post, you will stand still,
Go over the bridge, by the old water mill. 

Continue due North, to a fork in the road,
Where three coins found a humble abode.

On the northeast corner, where the four paths meet,
Lie two pieces of eight at the lone tree’s feet.

  

Before the horse enclosure, beneath a v-shaped tree,
Gold and silver doubloons are waiting for thee.

If you’re resourceful and swift, you'll find my loot
But leave it in place, or you’ll taste my cutlass and boot!