The original land mass of Earth, known as Pangaea, formed approximately 335 million years ago. It was a supercontinent that encompassed all of the Earth's current continents.

It's important to note that:

* Pangaea wasn't the first supercontinent. There were likely other supercontinents before it, but evidence is more limited.

* Pangaea wasn't the only supercontinent. It broke apart, and the continents continued moving, eventually leading to the formation of another supercontinent called Pangea Ultima, which is predicted to form in about 250 million years.

So, while we can talk about Pangaea as the most well-known supercontinent, it's not necessarily the original land mass of Earth.