posted by Funke .
It says write a story about a rock. Where it came from? How it got into my yard? What wearthering and erosion affected the rock
I have no idea of what type(s) of rock you have in your back yard.
Since this is not my area of expertise, I searched Google under the key words "weathering erosion of rocks" to get these possible sources:
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.