http://imgur.com/a/VPxqK is the image of the stamp. It is on the reverse side of an Indenture describing a lease between two yeoman in the County of York and dated 12 June, 1772. A friend owns the document and was asking me about it, but I know absolutely nothing about this period and my google searches aren't turning anything up - I think I have the wrong keywords. Any help identifying it would be amazing. Thank you.