Reference cited here are well known, but unfortunately rely upon a single letter "W" rather that "Y" in the supposed will to establish Lawton as the ancestral name. There are 15 other instances among the records of this William Layton using the name Layton (with a y). There is no suggestion that William wrote his own name either way since he made his mark (not signature) on at least one legal document.

I have made a detailed examination of transcribed documents and will be glad to send it to those may be interested rather than citing secondary sources.