I came across “The Old Families of Salisbury and Amesbury, Massachusetts, with some related families of adjoining towns and of York County, Maine” at this Internet Archive link.
There are many, many references to “Clough” in this book (including, but not limited to, John). You can read (and search) it online and even download a PDF to your computer.
If you’re not familiar with it, The Internet Archive is a 501(c)(3) non-profit and is building a digital library of Internet sites and other cultural artifacts in digital form. Like a paper library, it provides free access to researchers, historians, scholars, the print disabled and the general public.
This article first appeared in the JCGS blog under The Old Families of Salisbury and Amesbury, MA