Age of the Earth

At one time, may years ago it was commonly believed that the earth was only 6000 years old. This was because a man named James Ussher- who was a primate in the church of Ireland- he spent an extended period of time searching through the bible. He discovered that according to the bible, the earth was only 6000 years old. This theory was widely believed for many years. Then some people began to suspect that this may be false. These "geologists" probably began to suspect this because after watching how slowly change can happen on earth, such as fresh rock layers etc, they could see from looking at rock formations, that the earth has been around for a lot longer than hypothesized. This is evident by looking at things like the grand canyon. The river that runs through the canyon needed more time than 6000 years, this was true with many other rock formations around the world. This is why, in my opinion geologist began suspecting that the 6000 year estimate was false.