When visiting the Taihang mountains in Shanxi Province, he found fossilized sea shells and noted the presence of ovoid stones like those often found on the seashore, leading him to conclude that at some time in the distant past, Shanxi had been located by the sea.
看到山西太行山麓中夾有海貝的化石，與海濱往往有較圓潤的卵石，因而判斷太行山古時候臨海。