The Day the Mesozoic Died

For a very long time they couldn't figure out why there was thin clay layer around the earth's crust. Many had seen this layer and they started to gather information and missing pieces to this problem. They thought that since in places there were different types of rocks mixed together that there had to be a bigger cause then just natural processes. They had realized they were coming closer to the spot were they thought was a meteor. They finally used new tech to get a narrow area to search. They had finally found the spot where it landed. They have later discovered that there isn't any of the same species below KT boundary and above KT boundary. There had been many discoveries since then.