In geology, "-logy" is a suffix that indicates the study of.

So, "geology" itself literally means the study of the Earth.

Here are some examples of how "-logy" is used in geology:

* Petrology: The study of rocks

* Stratigraphy: The study of rock layers

* Paleontology: The study of fossils

* Mineralogy: The study of minerals

* Geomorphology: The study of landforms

* Seismology: The study of earthquakes

* Volcanology: The study of volcanoes

Essentially, any word ending in "-logy" in geology refers to a specific branch or area of study within the field.