Final answer:
The specific name of the drainage divide between west and east creeks in Unaweep Canyon is not provided, but it may be similar to the Continental Divide, which separates watersheds in North America.
Step-by-step explanation:
The name of the drainage divide between west and east creeks in Unaweep Canyon is not specified in the provided references. However, it is known that a drainage divide is the line marking the boundary between two drainage basins, where water on each side flows into different watershed areas. The description of the divide generally fits the Continental Divide, which is the principal, and largely mountainous, hydrological divide of North America. The Continental Divide separates the watersheds that drain into the Pacific Ocean from those river systems that drain into the Atlantic Ocean, including the Gulf of Mexico and the Caribbean Sea.
In the context of the literature and geological references provided, the passages hint at the unique geological and hydrological features of canyon landscapes, particularly in the American West. Terms like 'cross-cut of huge stone gullies' and 'deep canyons of mysterious source and outlet' support this. However, these passages do not clearly identify a specific drainage divide within Unaweep Canyon or other locations depicted.