On a recent trip to visit this area I noticed a unusual land formation, a spit of land that connects Frenchmans's Cove to the main part of the peninsula.
This spit of land is sometimes more commonly known as a Tombolo. The area of water that is contained by this Tombolo is known as a Barasway, in this case, Frenchman's Cove Barasway.
What is a Tombolo?
A tombolo is a sandy isthmus. A tombolo, from the Italian tombolo, meaning 'pillow' or 'cushion', and sometimes translated as ayre, is a deposition landform in which an island is attached to the mainland by a narrow piece of land such as a spit or bar. Once attached, the island is then known as a tied island.
Several islands tied together by bars which rise above the water level are called a tombolo cluster. Two or more tombolos may form an enclosure (called a lagoon) that can eventually fill with sediment.
How are they formed?
Over time (and this can take thousands of years, or it may or take place almost overnight, as in the case of a major storm rearranging sand bars) the shoreline moves toward an island due to sediments accumulating in the lee of the island where wave energy and longshore drift are reduced and therefore sand deposits occur.
Wave diffraction and refraction:
Basically, tombolos are formed by wave refraction and diffraction. As waves near an island, they are slowed by the shallow water surrounding it. These waves then bend around the island to the opposite side as they approach. The wave pattern created by this water movement causes a convergence of longshore drift on the opposite side of the island. The beach sediments that are moving by lateral transport on the lee side of the island will accumulate there, conforming to the shape of the wave pattern. In other words, the waves sweep sediment together from both sides. Eventually, when enough sediment has built up, the beach shoreline, known as a spit, will connect with an island and form a tombolo.
Unidirectional longshore drift:
In the case of longshore drift due to an oblique wave direction, the flow of material is along the coast in a movement which is not determined by wave diffraction around the now tied island, which it has reached. In this and similar cases, while the strip of beach material connected to the island may be technically called a tombolo because it links the island to the land, it is better thought of in terms of its formation as a spit, because the sand or shingle ridge is parallel rather than at right angles to the coast.
About this Cache:
Frenchman's Cove is a pair of small islands connected to the main part of the peninsula by 2 different Tombolos and are separated by a river that runs between them.
Logging requirements:
Remember, this is an EarthCache, so there is no physical container to find at the posted coordinates.
Your mission, to qualify for this Earthcache, is to gather some basic data at the narrow spot located at the posted coordinates along the spit of land that joins Frenchman's Cove to the mainland.
To claim this Earthcache as "Found", please contact me using the “message this owner” link at the top of the page, with your answers to the following items:
1. Once you arrive at the posted Coordinates, estimate the length and width of this Tombolo.
2. From your observations do you think this is a true Tombolo? Or is it a Spit?
3. How do you think this was formed? Wave Refraction and Defraction or Unidirectional Longshore Drift? See description above.
4. What is the height above sea level at GZ? You will have to stand on or near the pavement, not the rock sea wall that protects the roadway.
5. [REQUIRED] In accordance with the updated guidelines from Geocaching Headquarters published in June 2019, photos are now an acceptable logging requirement and WILL BE REQUIRED TO LOG THIS CACHE. Please post a photo in your log of yourself or your GPS – in your online log, taken along this strip of land – Be sure to explore Lions Den Rock on the other side of the Tombolo and the amazing rock formations it has to offer.