An early summary of them is found in Charles Lyell's .
In no way are they meant to imply there are no exceptions.
For example, the principle of superposition is based, fundamentally, on gravity.
In order for a layer of material to be deposited, something has to be beneath it to support it.
This orientation is not an assumption, because in virtually all situations, it is also possible to determine the original "way up" in the stratigraphic succession from "way up indicators".
I thought it would be useful to present an example where the geology is simple, and unsurprisingly, the method does work well, to show the quality of data that would have to be invalidated before a major revision of the geologic time scale could be accepted by conventional scientists.The layers of rock are known as "strata", and the study of their succession is known as "stratigraphy".Fundamental to stratigraphy are a set of simple principles, based on elementary geometry, empirical observation of the way these rocks are deposited today, and gravity.Much of the Earth's geology consists of successional layers of different rock types, piled one on top of another.
The most common rocks observed in this form are sedimentary rocks (derived from what were formerly sediments), and extrusive igneous rocks (e.g., lavas, volcanic ash, and other formerly molten rocks extruded onto the Earth's surface).
Most of these principles were formally proposed by Nicolaus Steno (Niels Steensen, Danish), in 1669, although some have an even older heritage that extends as far back as the authors of the Bible.