J. Tylor & Sons were a firm of Engineers (but see below for a more detailed description).
They operated from:
2 Newgate Street,
at the time the underprint was in use.
A Post Office Commercial Directory for 1865 has an entry for the firm that reads:
This Brassfounders firm was owned by a Quaker Joseph Tylor. His two sons Alfred and Edward both worked for the family business. After seven years working for the firm, the younger son, Edward left due to ill health and travelled widely. He later became Sir Edward Tylor, Professor of Anthropology at Oxford and head of the University Museum. The picture below of Sir Edward is a detail of a chalk drawing by G. Bonavia held in the National Portrait Gallery, London.
1868. Unofficial underprint type 59 (under the gum) in black.
a) Vertical underprint, reading upwards
PP196 1d lake-red (SG 43 or G1)
b) Vertical underprint, reading downwards
PP197 1d lake-red
(SG 43 or G1)