The pit holds millions of bones of just about every type of animal on the island. At the absolute bottom, unseen unless see invisible is used is a sword +1 +3 vs. dinosaurs*, across a 3-foot diameter hole. The hole goes down 4 miles to the lost world.
Wandering monsters among the bones
• d6 giant scorpions: AC2, HD4, hp 20, 15, 17, 16, At 2 claws/1 sting (at +2 if claws hit), D1-10/1-10/1-4+poison, save F2, C.
• d6 scorpions: AC5, HD1/2, At 2 claws/1 string, D1-4/1-4/1-2+poison (save at +1), save NM, N.