Geode Issues

Hi all, I have a couple of questions. I did manage to get surface geodes working last night, but this current one is causing errors and preventing the world from being loaded. I was hoping there that someone could figure out what parameters I set incorrectly to cause it. I know it's in the geode here specifically; I was just hoping a spare set of eyes could spot the issue.
Secondly, how can I go about making sure that the geode is always flat? I don't want it to have slopes at all, as it would lead to the lava acting weirdly.