Modern digital elevation models (DEMs) of Nutty Putty show that The Birth Canal has a negative slope coefficient. In layman's terms: it gets tighter as you go in. Standard USGS topographic maps don't capture this, but the speleological map uses cross-hatching to indicate "crawlway with vertical clearance under 12 inches."
The standard 2D map provides a "bird's eye" look down into the cave system. nutty putty cave map
Crucially, the map labels an unnamed, narrow, upward-sloping passage near the entrance of . This was an undeveloped, dead-end fissure – not a through-route. On most modern maps, it is marked with a warning symbol (e.g., “Tight squeeze – no exit”). Modern digital elevation models (DEMs) of Nutty Putty