| George Wostenholm (I*XL) — stamps, I*XL, two works (Rockingham → Washington Works) | 1797 → at least 1991 | 6 | The key to dating is the factory address: Rockingham Works until 1847, Washington Works from 1847. The firm itself gives different founding years (174 |
| Country mark (lower bound, NOT a year) | the requirement applies from 1 March 1891 (Tariff Act of 1890, also known as the McKinley Tariff) | 2 | A country mark is only a LOWER BOUND (the item is no earlier than the introduction of the marking) and never a year. For Wostenholm the mark ENGLAND i |
| Grind, spine, scales, etching — era markers of a straight razor | 1700s → mid-1900s | 16 | Shared layer for all straight razors: it does not date precisely, but it cuts off an era. All rows are printed wordings from a shop-page guide review |