In general, the deeper the fossils are in bedrock, the older the organisms are that they represent. This is because the older rocks and fossils tend to be buried deeper over time, as newer layers are deposited on top. Additionally, geological processes such as tectonic movements, erosion, and weathering can further bury older layers, making them more difficult to access and leading to a deeper position within the rock layers. So, when studying the fossil record, scientists use the depth of the fossils within the rock layers as a key factor in determining the relative age of the organisms that they represent. By comparing the depth and position of different fossils within a site, scientists can build a more complete picture of the evolution and development of life on Earth.