The fractured rock layer found at the edge of continents is called the continental shelf. It's not exactly a "fractured" layer, but rather a submerged extension of the continent.

Here's why:

* Formation: The continental shelf formed millions of years ago when sea levels were much lower. As sea levels rose, they flooded these low-lying areas, creating the submerged shelf.

* Composition: It's composed of various rock types, including sedimentary rocks deposited over millions of years. These rocks are often fractured due to tectonic activity and erosion.

* Importance: The continental shelf is a vital part of the ocean ecosystem. It provides rich fishing grounds, supports diverse marine life, and is a major source of oil and gas deposits.

Important Note: The term "fractured rock layer" isn't a standard geological term. While the continental shelf does contain fractured rock, the term itself refers to the submerged portion of the continent.