What is "patharkat"

The Patharkat are a Hindu sub- caste found in North India. The majority of this subcaste in Nepal, Kushbadiya, speak a poorly known language, and exhibit enough distinct cultural values to be a separate ethnic group, nevertheless Pattharkat in Kapilbastu District are exceptional as they considered themselves to be Dalit rather than adivasi. In India, they are also known as Sangtarash.