"The 'R' type is an oval similar to Nicholson's R-8 among the registration postmarks (pp. 221-222). Were these postmarks prepared for all Post Offices for use as real registration marks and then not placed in use as such, but sent out later for use on regular mail with the 'REGISTERED' blocked out? The blocking out was not well done and either the full word still appears or a smudge. TOWER ISLE in 1953 shows the smudge but in 1954 has the only 'R' I have seen in which no 'REGISTERED' appears. The town and Jamaica appear at the bottom and the date is usually expressed as day (numeral), month (two letters) and year (with 19 omitted) in one line in the centre. Towns with 'REGISTERED' still appearing in full: BALCARRES, FLOWER HILL and TROY Towns with 'REGISTERED' partially defaced: ABERDEEN, ABOUKIR, ASHLEY, BAILEYS VALE, BROADLEAF, CALDERWELL, CARISBROOKE, COLEGATE, ESSEX HALL, LEEDS, SANDY RIVER, TRANQUILLITY, TWEEDSIDE, WHITHORN and WINDSOR FOREST. ABOUKIR and BAILEYS VALE appear in violet; WHITHORN has the date upside down; the month precedes the day in BALCARRES, FLOWER HILL, TOWER ISLE, TRANQUILITY, TWEEDSIDE, WHITHORN and WINDSOR FOREST. This is of course, not a complete listing of these 'R' types.
'N' TYPES.
The 'N's' are modifications of the Birmingham type with the unsightly curved black slugs removed but the measurements remain the same. In some 'N's', a curved line, equidistant from both lines of the double circle, replaced the Birmingham slug. Town is at the top and Jamaica at the bottom within the double circle. The 'N's' normally have a star at the top, month (in two letters ), the day in the centre line and the year (19) omitted below. But this is the most crazy mixed-up type of postmarks in recent years. Either some postmarks were sent out without stars or postmasters removed them as a nuisance the dates appear in all conceivable positions within the inner circle.
'N'
This taken as the normal type although it has fewer towns by far than 'Na' or 'Nb' has the line within the double circle replacing the slug and the star above the date appears on: CORNWALL MOUNTAIN, FAIRY HILL, MILE GULLY,MONTEGO BAY, MULGRAVE, OCHO RIOS, PLEASANT VALLEY, PORT MORANT and REFUGE. PLEASANT VALLEY appeared in violet in 1953; REFUGE had the month upside down."