<p>@thisislife</p>
<p>There is not a lot in Historical Geology that is difficult to understand but unless you are a lot smarter, or have a much better memory, than me you have got to spend more than an hour a week on it. It takes time to learn all the subdivisions of the Paleozoic like the Ordovician and how long ago it was (I think about 400 million years ago) and the major life forms that emerged (fish, I believe) and the location of the continents and what they were like Pangea or Laurasia. You have to know that the Apallachian mountains formed around 400 million years ago when what is now North Africa collided with what is now Eastern North America. And this is just scratching the surface. It is a lot to remember but if you spent an hour a day on it you could probably get an A in the class.</p>