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Ship Harbor Earthcache

Hidden : 4/29/2008
2 out of 5
1 out of 5

Size: Size: other (other)

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Geocache Description:

The Posted Coordinates will bring you to a sign explaining more about the geology of Ship Harbor and help you understand what you see here. Use your own observation skills to log the cache. If you are not sailing, you can walk in to the lot for free.


1. A Photo of you and your GPS overlooking the Harbor from the coordinates (prove of visit – no virtual finds please)

2. Give your estimate of how much of the harbor has filled in so far. Either you can estimate the distance from the old shore line to the current one, or a harder task, estimate the number of acres of land that used to be harbor.

3. Bonus Question: Tell in your log about another harbor that is silting up and what effects there are from the situation.


Much of the San Juan Islands are comprised of solid rock thrust up by movement in the Earth’s plates, but not the land at Ship Harbor. What you see here is the result of ocean waves and currents depositing material into the harbor. The result is low lying marshland that is gradually drying out and firming up.

Much like rivers deposit material as they meander, and gradually change course, the ocean will deposit material given the right topography and surrounding geological conditions. In this case the rock coastline is relatively fixed (though as the rocks wear they provide the sand here) and the ocean is slowly filling in the harbor area with silt and sand.

This process may take centuries, and Washington State modern history is pretty short. Therefore, to understand the potential effects of harbor siltation, we turn to another more famous, but similar example of this geological phenomenon.

The ancient city of Ephesus, in what is now known as Turkey suffered a similar geological fate to Ship Harbor. While Ephesus was founded in the 10th Century BC (before 1000 BC) in a great spot for trading by ship, the river Cayster (today Küçük Menderes) and the action of the ocean silted up the harbor over time. The resulting marshes caused malaria and many deaths in the area. To solve the problems of silt and disease, the king flood the old city by blocking the sewers in about 290 BC. The people of Ephesus were forced to move to a new settlement 2 kilometers closer to the sea.

Moving the city (and repeated harbor dredging) worked for about 1400 years. Ephesus survived as an important center through multiple invasions, and under different empires. However, in the end it was silt in the harbor that ended the importance of Ephesus as a commercial centre. With no more easy access to the Aegean Sea, residents started leaving the lowland of the city for the surrounding hills and beyond. By 1073 Ephesus was but a small village. Today it is an important tourist destination, but don’t expect to see the harbor that built the City from the ruins because you will need to go 5 kilometers to get to the sea!

Additional Hints (Decrypt)

Jnvgvat sbe n Fuvc ng gur Uneobe? Qb gur Fuvc Uneobe Rnegupnpur! Rnfg/Evtug fvqr bs gur cnexvat ybg.

Decryption Key


(letter above equals below, and vice versa)



936 Logged Visits

Found it 921     Write note 12     Post Reviewer Note 1     Publish Listing 1     Owner Maintenance 1     

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Coordinates are in the WGS84 datum

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