I found an odd looking stone at Khobak 

Stone jars also known as Longthainiara or Lungzubel are reported from 10 sites in the southern part of Dima Hasao district in Assam. These jars are similar in shape to those found in Laos DPR. Some scholars have claimed it to be an ancestral bone repository created by the group of austro-Asiatic speakers in the circa first century CE. Although this is a presupposition and further scientific investigation is required.
P.S: The Biate community rediscovered it in the late nineteenth or early twentieth century CE. They reused it for storing rice beer until their conversion into Christianity and called them as Lungzubel (Lung = Stone + Ju = alcoholic drink + bel = jar).
Stone jars can be translated as longthainiara in the Dimasa dialect (largest ethnic community in the district).