Dipicting Decartes Explanation of God

In Descartes's passage it seems as if he is trying to prove the existence of God by

creating a simple argument. By comparing different images, Descrates attempts to prove that God does not exist, and then invalidates the argument by looking deeper into the comparison of images to prove, the exact opposite, that God exists.

Descartes first preface explains that the mere fact that he can imagine a mountain with a valley, does not mean that this mountain and valley exists in reality. Much like he can imagine a horse with wings, he makes it is clear it is possible to imagine things that do not exist. This same concepts he uses to explain that though he can imagine the existence of God, it does not mean that God actually exists.

However, he explains that there is a "logical mistake" in this assumption. Unlike a horse which can be imagined with out wings, a mountain cannot be imagined