system
Given the following post, respond as if you're commenting on Reddit:
human
Does geology play a part in showing the average temperature of the Earth in a certain time period, like the chemical makeup of the rocks? Or is there more to it in determining geologically what the climate was like in the past?

Had someone mention in another thread that we have historical data on temperatures obtained by geology studies that shows the climate currently doesn't match with the general trend we'd expect to be naturally occurring, so I'm curious as to if there's something geologically that shows the Earth's average climate in comparison to now, and how that shows it's much warmer now than it should be by natural progression.
gpt
The rocks generally just offer insights to the climate of the time. Showing us if it was deep sea, continental shelf, delta, beach, grassland, moorland, mountainous, jungle, forest etc

Fossil evidence can show the cycles of population booms and falls over millions of years, pointing to ecological instability through many factors such as climate.

Now, Ice... Ice can offer much more, over a much smaller time period 

Ice traps air, and we can find the chemical composition of that air to determine the global temperature. Through this method we've been able to track Carbon concentrations over thousands of years.