 So this little schematic drawing kind of shows the parts of isocity that are right and the parts that aren't right at the same time. So see how this is a cross-section of the Earth. And here's a continent. And then this is the sea floor. And you can see that this mountain belt has a root underneath it. This is right. This is a pretty good cross-section of what the cross looks like. And then the idea for how you end up with ocean in between two continents, for some people, was, well, you had this bit of continental crust, and it sank down into the mantle. And now these two things are separated by ocean. But let's remember that the contracting Earth hypothesis didn't allow for any lateral motion of the crust, only vertical motion. So it leads you to wonder how this ocean crust could get here. Where did it come from? If you have this land that sinks down, and now you have some ocean crust that pops up, how could you do that if all you can have is vertical motion? Well, you can't. It doesn't work. And so this is sort of one of the limitations of this hypothesis. And it was mechanical problems like this that people just kind of swept under the rug, because they couldn't explain them. And so they just didn't think about it anymore.