The geological profile presents a view to the north, as if looking at a vertical slice from east to west through the side of the hills. It shows the Warren’s Shaft system and Hezekiah’s tunnel in relation to prominent features and the underlying rock types. The vertical lines mark geological faults, cracks in the ground that have caused vertical displacement of the layers. Here we can see that while the uppermost portion of the Warren’s Shaft system lies in the porous Meleke layer, the rest of the system, all of Hezekiah’s tunnel and the Gihon Spring itself lie in the hard Mizzi Ahmar dolomite layer.