Noun
The science which treats of rocks, as regards their mineral constitution and classification, and their mode of occurrence in nature.
A treatise on stones found in the body.
Source: Webster's dictionaryA bed is defined as a layer of rock that has a uniform lithology and texture. Source: Internet
The Alps are subdivided by different lithology (rock composition) and nappe structure according to the orogenic events that affected them. Source: Internet
On the other hand, when a rock layer with a certain age is followed laterally, the lithology (the type of rock) and facies eventually change. Source: Internet