Originally posted by Malistair:

Generally speaking swamps are pretty cluttered with Crypts if they are large enough. The thin "bacon strip" zones are sparsely populated from my experience. You need a nice sized zone like Species posted to get a good population of crypts. That place you lovingly named "hell" looks like it may host upwards of about 10 if you are lucky.

Sadly 'Hell' is on the very edge of where the biome becomes black forest. So, what's revealed is the extent of the biome. I guess it'd be larger if it didn't have a big body of water running through the middle of it.