《徐霞客游记·粤西游日记二十六》
向西穿过其中，又走半里开始下行，便向西下坠半里来到坞底。
西穿其间，又半里始下，乃西坠半里至坞底。
Passing through the gap to the west, they went down another half a li and descended to the bottom of a valley.
<s>[INST] Kindly elucidate the central themes in this passage in English: 西穿其间，又半里始下，乃西坠半里至坞底。 [/INST] Passing through the gap to the west, they went down another half a li and descended to the bottom of a valley.</s>
Kindly elucidate the central themes in this passage in English: 西穿其间，又半里始下，乃西坠半里至坞底。
user
Passing through the gap to the west, they went down another half a li and descended to the bottom of a valley.
assistant