Bava Batra 61: Annexes and Cisterns
A new chapter - with a new mishnah! If you sell a house without specifying that attachments or annexes to the house are included in the sale, then they are not included. The Gemara addresses these "attachments" and what happens when they are cisterns, for example, of a size of 4 amot - because smaller than 4 amot would be included in the sale, according to Mar Zutra.