Theconcept of geologic time or deep time was a logical consequence of this theory.
In 1788 John Playfair came to see Hutton’s Unconformity in Inchbonny.
The realization that sediments turn into rock was counter to the view that all rocks on Earth formed in a single creation event.
Once Steno recognized that the fossils he was contemplating (sharks teeth and sea shells) were formed in the sediments of oceans he was able to work out the basic rules of stratigraphy.
The unconformity consists of many vertical tilted layers of grey shale overlaid by many layers of horizontal red sandstone.