It looks like it was made by a creature and isn't natural, though it seems like it may follow some natural cracking in the foundation of the place. Very smooth and very wet looking from what you can see, and it forks. Perhaps some smaller creatures use this to move through the place.
"I'm fer pickin a direction and gettin ourselves away from this here door," Koregar said softly to the others. "That ugly feller's gonna get out o' that coffin soon enough, and when he does, I don't want it to be smellin my manly musk and knowin where we went."
As he walked down the hall to where the dark elf was, he had to pull his eyes away from the gem. It was a nice one, but the girl was right. It could have some nasty magics laid on it.
"Magic? Err...yes...I've studied and dabbled a bit. Unfortunately determining if that is magical or not is beyond me at the moment. I assume it is and dangerous to boot. My name is Siljar, by the way. I've lost my master and my way." Then with a smirk "I'm not so worried about the drow as I am about a halfling with sticky fingers and a knack for opening locks..."
Rumaging through his pack: "well...I seem to have a quill and ink but no paper. We should probably map our way in case we need to back track. I suppose this will do for now." He pulls out a page with a letter written on one side and starts to sketch the area in rough detail on the back of it. Then he moves up to where the drow is and examines the door for any clues as to the meaning of the faces and colors.
Perception is +2 investigation is +5. Raw roll: [roll0]
Whisper silently held up her hands and shrugged her shoulders, as if to say, "Who? Me?" Feeling distinctly alone at the end of the corridor, she followed the rest of the group to catch up with the drow.
Koregar meanders his way to the right, to the room with the pillar, trying to walk softly and not be heard by anything that might find "dwarf" to be particularly tasty. Not that he was afraid, mind, but he didn't get to be 200 years old by being a durned fool.