Lynn Carter

And these are some of the blocks.

So this is a 100-meter scale bar.

And these are giant rocks that have been thrown out by an impact.

And you can see tons of layering in these rocks, too.

And we think these were thrown out by very large impact craters that could have excavated things from really below the surface.

And so these rocks, probably things that were from originally below the surface and they've been chucked out onto the surface.

So we can also visit the site and look at these rocks, possibly even older than some of the other rocks that we knew were there.

But of course, we don't have them in stratigraphy.

They're just like rocks that were thrown onto the surface and become part of the terrain.

So then the other place is Jezero Crater.

So Jezero Crater, the thing that people like about it is that unlike at Northeast Sirtis, there's a clear story for there being liquid water here.

So this is an open basin lake where water once filled this crater and then ran out the other side.

So we know there's water in here because we can see an outlet channel.

So water filled in here and then it ran out and it deposited this delta.

So there was standing water here.

We don't know there was standing water at the other site.

We just know that there's really old rocks and that they're very interesting rocks.

And they're all in stratigraphy.

Here, we wouldn't have access to that stratigraphy all laid out in those beautiful mesas.

Instead, what we would be doing is looking at rocks that got eroded from up here and were carried down this river channel and deposited into this basin.