Geologic layers, also known as STRATA, are layers of sedimentary rock that have been formed over time due to the accumulation of materials such as minerals, organic matter, and fossils. These layers can be used to study the history of the Earth and its environment, as they provide a record of the changes that have occurred over time. STRATA can also be used to identify different types of rocks and minerals, as well as to determine the age of the rocks.