Summoning Structures adding to game useful Spawners (But its not dull spawners or sad mod with crafting default minecraft spawner block). It`s multiblocks spawners. It has 6 (in this moment) multi-blocks spawners of mobs!
List mobs which you can spawning with mod Summoning Structures:
Zombie PigZombie EnderMan Creeper Blaze Skeleton
To get started you need crafting blocks for creating Spawner:
x8 Type of mob spawn block if you want spawning x8 Base Block x8 Decalithium Bars x1 Spawner Core
Good luck with using mod!
Thanks to Alego22 (textures), SeqSee (Codding), seia6666 (Structures).