AP BIOLOGY

Detailed explanation-1: -Trilobite fossils can be found in most Paleozoic sedimentary rocks throughout the world.

Detailed explanation-2: -The fossils are found in a limestone shale. This shale splits easily into flat sheets, revealing the trilobite fossils. Fossilized trilobites lay nearly flat along the splitting planes of the shale.

Detailed explanation-3: -Mudstone, shale, and limestone are examples of sedimentary rock likely to contain fossils. As the layers of sediment build up on top of one another, they create a physical timeline. The oldest layers, along with the organisms that were fossilized as they formed, are deepest.

Detailed explanation-4: -Fossils are typically found in sedimentary rocks and occasionally some fine-grained, low-grade metamorphic rocks. Sometimes the fossils have been removed, leaving moulds in the surrounding rock, or the moulds may have later been filled by other materials, forming casts of the original fossils.