" had been away on a distant plantation and was riding slowly home in the evening, when my eye fell upon something all huddled together at the bottom of a steep nullah. "
Source: The Collins English Dictionary © 2000 HarperCollins Publishers:

nullah ['nʌlɑː]
noun a stream or drain
[ETYMOLOGY: 18th Century: from Hindi nala]

Another site gave "ravine".

Interesting that period of profiting of Indian natural resources and language, too...