Here is the Lailai geological area. In addition to the special coastal landscape, it is also a very popular rock fishing spot because it is the most well developed wave-cut platform around the Northeast Coast area. From here, you could see the special landscape called the Devil’s Washboard. Those neat traces of bumps on the coast, just like a huge washboard laying on the coast. Why it become the way it is? Let’s learn about the wave-cut platform and solve the mystery of the devil's washboard!
這裡是萊萊地質區，除了特殊的海岸景觀外，也因為這裡是東北角海蝕平臺最發達的地區而成為熱門的磯釣地點。在這裡，你會看到一道道凹凸起伏的痕跡，就像這片海岸是一塊巨大的洗衣板一樣。為什麼會有這樣的現象呢？讓我們一起深入了解並解開魔鬼洗衣板的謎團吧！
Wave-cut platform / 海蝕平台
A wave-cut platform, shore platform, coastal bench, or wave-cut cliff is the narrow flat area often found at the base of a sea cliff or along the shoreline of a lake, bay, or sea that was created by erosion. Wave-cut platforms are often most obvious at low tide when they become visible as huge areas of flat rock.
Wave-cut platforms form when destructive waves hit against the cliff face, causing an undercut between the high and low water marks, mainly as a result of abrasion, corrosion and hydraulic action, creating a wave-cut notch. This notch then enlarges into a cave. The waves undermine this portion until the roof of the cave cannot hold due to the pressure and freeze-thaw or biological weathering acting on it, and collapses, resulting in the cliff retreating landward. The base of the cave forms the wave-cut platform as attrition causes the collapsed material to be broken down into smaller pieces, while some cliff material may be washed into the sea.
海蝕平臺，又稱波蝕棚、浪蝕臺，是海邊懸崖下的一個狹扁的平臺。平臺的形成需要相當長的作用時間，一開始海崖受到海浪沖刷，在海面高低潮線的位置向岩壁侵蝕，形成凹洞。凹洞會隨著時間漸漸形成較深的洞穴，在海水的持續沖刷下，洞穴無法承受上方海崖的重量而崩塌陷落，崩落後的石塊也因海水沖刷碎成小石塊被海水帶走，於是懸崖峭壁逐漸往陸地退後而海蝕平臺日益擴張，最後才形成寬廣的海蝕平臺。海蝕平臺一般向海傾斜，其寬度與波浪作用的強度有關，波浪作用強的地方海蝕平臺寬度大，但其表面不平坦，有時會留下海蝕柱、礁石、浪蝕溝等。
The Wave-cut platform in Lailai area is the Datongshan layer formed in the Oligocene (about 34~23 million years ago): It is composed of thin-to-thick extremely fine-grained sandstone and hard shale sandwiched by shale, and then interbedded with a thin layer of fine-grained sandstone.
Due to the long-term beating and erosion of waves, the squeezed and folded rock formation flattened to the same height to form a flat Wave-cut platform. However, the interbedded sandstone and shale rock on the platform still have a soft and hard difference. The result of erosion has formed a wrinkled texture like a washboard, making this place called “the devil's washboard”.
萊萊地區的海蝕平臺，地層大約為漸新世(3400~2300萬年前)形成的大桶山層：由頁岩夾著自薄至厚的極細粒沙岩及硬頁岩，再與細粒沙岩之薄層互層構成。受擠壓皺褶的岩層，由於海水長期的拍打與侵蝕，削平成同一高度形成一個平坦的海蝕平臺。但平臺上的沙岩與頁岩互層岩石仍有軟硬的差別，經過長年累月侵蝕後，就形成了你們眼前看到如同洗衣板般的皺褶紋理。
You'll have to visit here at the low tide to have a better observation and answer the questions, please check the tide table before you visit this earthcache.
※請注意: 為了能更好的觀察並回答問題，請於退潮時段造訪此處。出發前請先確認潮汐表。※
To log this cache, please answer the following questions:
1. Please walk on to the devil's washboard and observe the protrusions and depressions of the Wave-cut platform carefully.
請走到魔鬼的洗衣板上，仔細地觀察海蝕平臺的凸出處與凹陷處。
- Please describe the characteristics (color, hardness, touch) of the stone composed of the protrusions and depressions of the "devil's washboard".
請描述"魔鬼的洗衣板"凸出處與凹陷處組成的石頭特徵 (顏色、紋理、觸感、硬度等)。
- Based on your observation, please try to determine which kind of the stones that compose the protrusion and the depression?
根據你的觀察，請判斷凸出處與凹陷處分別是哪一種岩石？
- Please explain your answers to the above questions.
承上題，請說明你如此判斷的理由。
2. Please observe the crag that behind the Wave-cut platform. On this well-layered crag, you can see how the ground here is stacked.
請仔細觀察海蝕平臺後方的岩壁。在這塊層理分明岩壁上，你可以看到腳下的土地是如何堆砌而成的。
- According to the characteristics of different layers of rocks, please try to determine their rock types, and compare it with the depressions and the protrusions of the devil's washboard on the Wave-cut platform, try to determine whether the composition of the rock wall is the same as that of the Wave-cut platform.
請依照岩石不同分層的特徵，試著判斷它們的岩石類型，並將它與海蝕平台上洗衣板的凹陷與凸出處做比對，判斷岩壁的組成是否與海蝕平台的岩石組成相同。
- Why do you think the distinct layers of rock on the crag will form washboard with different directions on the Wave-cut platform?
你覺得為何岩壁上層層分明的岩層，會在海蝕平台上形成方向截然不同的洗衣板？
- Please observe whether there are signs of erosion on the rock wall, and based on your observation, presume whether the sea erosion platform will extend to the land in the future? If so, will it look similar to the current washboard?
請觀察岩壁是否有侵蝕的痕跡，並且根據你的觀察來推測海蝕平台是否還會繼續往陸地的方向延伸？如果會的話，是否會呈現跟現在相似的洗衣板樣貌？
3. Who broke my washboard?
誰弄壞了我的洗衣板？
- On the "devil's washboard", you can see that different from the washboard parallel to the sea surface, there are several cracks that often extend perpendicular to the washboard. Please observe the length of these cracks and where they extend to, and try to presume how these cracks created?
在"魔鬼的洗衣板"上，你可以看到有數道與洗衣板呈垂直方向延伸的裂痕。請觀察這些裂痕的長度以及它們延伸到何處，並且試著推測與解釋這些裂痕是如何產生的。
4. Take a photo with the devil's washboard in the background, the photos must contain either you (no face required), your personal item, a piece of paper with your geocaching name, or any else that would makes your photos unique.
請以"魔鬼的洗衣板"為背景，拍照上傳。
Notes:
- Please don’t post any answers in your log.
- Please send the answers to the owner via message system of geocaching.com. Only the accounts that sent the answers could log as found, so please make sure you sent your own answers even you’re in the group-hunting.
- You MUST visit the earthcache location to claim a find. I’ll delete the logs of people who clearly didn’t visit the earthcache or who didn't complete the logging tasks.
- You don’t have to wait the permission to log after you send the answers. Any logs without all of the answers will be deleted.
REF: 經濟部中央地質調查所彙刊(第29號), 國立自然科學博物館(館訊第313期第五版), Wikipedia, EB Education