Sentence:  Turning to the left and skirting this huge hedge Treebeard came in a few strides to a narrow entrance. Through it a worn path passed and dived suddenly down a long steep slope. The hobbits saw that they were descending into a great <WSD>dingle</WSD>, almost as round as a bowl, very wide and deep, crowned at the rim with the high dark evergreen hedge. 
Meaning of the word marked with <WSD> tags:  A small, narrow or enclosed, usually wooded valley.