If I understand this chart correctly, all groups that have a line connected to each other share a member. The Cofagrigus line is both in the amorphous/indeterminate group and mineral group, and therefore the two groups are directly connected. Do I misunderstand the breeding chart?
http://imgur.com/AEwSWRn.jpg
http://imgur.com/cjRHMOE.jpg
This was changed a while back to use a simpler table instead.