If there is a border or a sea quill plant in the middle of a field, it separates the field regarding certain halachot but not others. One case it works for is acquiring land that belonged to a convert who died (hefker). One opinion is that is is not considered a separation for carrying on Shabbat and Rava says that it is. The exact details about what this means are described in the gemara. If there is no border, how much of the field goes to the one who acquired it? The gemara then discusses that the sea quill was used by Yehoshua to demarcate borders between the tribes when he conquered Israel. From there the gemara mentions another issue relating to Yehoshua and then one relating to the borders of Israel that Moshe was shown by God right before he died which are the ones that are obligated in tithes. The ones excluded from this are the lands that belonged to other neighbors (not from the 7 nations) – the Kini, Knizi and Kadmoni. There is a 3 way argument about what geographic areas this is referring to. The next mishna and gemara discuss issues regarding testimony about the 3 year chazaka. Can 3 groups of witnesses testify each about a separate year? Is this considered a whole unit of testimony (which is acceptable) or a part of a testimony (which is not acceptable)? What if 2 witnesses testified about all 3 years but disagreed about which type of produce the person benefitted from? Would their testimony be accepted?