In Notch's post announcing the release of this version on The Word of Notch, he included an image of a level preview tool to show how the terrain looks in this version. A monolith can be seen to the right of the image, near the coast. Monoliths were not discovered/documented until late Alpha, so it is surprising that the very first publicly shown image featuring this terrain generator contains one.
Gallery
An image taken from the blog post accompanying this version, with a monolith visible on the right of the image.