1 Eleven: This is the spike pit that can only be bypassed by magic?
2 Lucas: Or extreme cleverness.
3 {beat}
4 Eleven: Magic it is.

This is indeed the spike pit, with 200 spikes. It's ten feet wide (the full width of the corridor) and 20 feet long, so beyond jumping over for non-elite-athletes. The adventure module states explicitly that the obvious method of traversing the pit is simply to climb down, walk carefully across the floor avoiding the spikes, and climb back up the other side. Of course if the party attempts this it actually springs a deadly trap. As previously stated, there's no way to cast and attach a rope to the other side.

The adventure states the only way to safely get across is to use magic, such as a Fly spell. Though if I were actually running this, I'd certainly allow other clever non-magical methods.