Step 2: mash cookies and chocolate
Since there are 3 distinct periods for dinosaurs (Cretaceous, Jurassic and Triassic) I figured on using 3 type of goodies as my 'rocks' in the layers of cake: Ladyfingers (cookie), chocolate filled wafer sticks (biscuit), dark chocolate and burnt almond bar (chocolate bar).
Almost any type of biscuit or cookie can be used, giving you different textures. Some alternatives might be sandwich cookies (like Oreo and Pirate), specialty cookies (like ginger-molasses cookies or Arrowroot), or any type of chocolate bar (the more goodies inside the better!).
Using kitchen scissors these were all cut into chunks and placed in small bowls to be added to our cake later.