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Taxonomic Nomenclature

By Jon Saxton    |   Monday, 3 June 2002

The following content comes from the Jon Saxton personnal website last updated in 2001, which not longer exist since around 2018. To keep this information available to the public and for a perpetuity reason, we reproduced it here.

This page documents my attempt to devise a short, systematic notation for the Commonwealth coinage of Australia.


I have been collecting Australian Commonwealth coinage for some time and I have always been very interested in die varieties. Recently my collection has grown somewhat to the point where it is difficult for me to remember the varieties for any individual denomination and year. Now I want to catalogue my collection and identify each coin with a short but meaningful code.

Of course it is always possible to spell out the detail:

  • 1943 Melbourne penny
  • 1943 Perth penny
  • 1943 Bombay penny
  • 1943 Bombay penny with 1942-style denticles on the reverse

but that is a bit unwieldy. Another approach would be to use a code from one of the standard catalogues. For example, Clarke's fifth edition lists the four coins above as 99, 100, 101 and 101a respectively while Renniks fourth edition lists them as B45, B46, B47 and B47A. One trouble with any such scheme is that it is tied to a specific catalogue which may not list every variety. (Renniks editions after the 11th do not list varieties at all, nor does the popular McDonald's catalogue.) A more fundamental problem for me is that the catalogue designators just don't have any intrinsic meaning. Neither 100 nor B46 says "1943 Perth penny" to me. I want a code which is useful and easy to interpret and which doesn't mean that I have to carry a cagalogue with me at all times.

A much better notation was used by John Dean in his 1965 Australian Coin Varieties Catalogue in which the pennies listed above were designated P43A, P43B, P43C and P43D. The first letter denotes the denomination, H for Halfpenny, P for Penny and so on. The following two digits designate the year of minting. Since all Commonwealth coinage was minted in the 20th century, two digits are quite sufficient. The trailing letter denotes the variety. There is a certain attractive simplicity to Dean's notation and for a while I used a slightly modified version thereof.

Dean's catalogue was a remarkable achievement for its time and his naming scheme goes a long way towards a catalogue-independent notation. It just doesn't go far enough and does not address any of the modern classification schemes systematically. This became obvious to me even before reading Paul Holland's articles on the classification of the bronze coinage according to master die types.

Reading through auction lists it is obvious that people construct their own informal shorthand notations for varieties. I have often seen "1943-I penny" used for the Bombay issue and "1943-Y." for the Perth issue. Each of those is descriptive, simple and unambiguous. The only problem with such a notation is that it is hard to extend to less obvious but equally important varieties such as the 1927 pennies with the London and Calcutta obverses. Nevertheless the informal notations set the standard for simplicity and ease of use.

Taxonomic nomenclature in biology

Taxonomic nomenclature is used in biology to classify living organisms according to a heirarchy of inter-species relationships with the most generic at the top and the most specialised at the bottom. Familiar terms such as escherichia coli and homo sapiens are examples of taxonomic names. Common practice in biology is to use only the two lowest taxa so that in the examples just given, escherichia and homo name the genus while coli and sapiens name the species. The taxonomy for modern man is:

  • Kingdom - animalia
  • Phylum - chordata
  • Subphylum - vertebrata
  • Class - mammalia
  • Sublass - eutheria
  • Order - primates
  • Family - hominidae
  • Genus - homo
  • Species - sapiens

Biological taxonomy is based on evolutionary relationships between organisms at any level. It is just one of several classification schemes and is chosen because it happens to be the most useful. Other taxonomies are possible.

An important feature of the biological taxonomy is that each taxon is more generic and so more inclusive than the taxa below it. There are more organisms in the order primates than in the family hominidae. Furthermore, each taxon is a proper subset of the taxa above. All primates are mammals. You don't find any which are reptiles.

Taxonomic nomenclature applied to Australian Commonwealth coinage

Australian coins lend themselves to taxonomic classification based on something akin to evolutionary relationships. For example, all threepences are similar but the threepences of George VI are more closely related to each other than to an Edward VII threepence. Again, multiple taxonomies are possible but take the following as examples:

One possible taxonomy for the 1942 and 1943 pennies

Denomination Penny Penny Penny Penny Penny Penny Penny
Year 1942 1942 1942 1943 1943 1943 1943
Obverse master die 3 4 4 3 3 4 4
Reverse master die D E E D D E F
Mint Perth Bombay Bombay Melbourne Perth Bombay Bombay
Variety I mint mark No I
Designator P42-3D-P P42-4E-B-1 P42-4E-B-2 P43-3D-M P43-3D-P P43-4E-B P43-4F-B

One could argue the importance of the characterstics. Should year of issue be ranked above the master die types as in the tables shown above? Perhaps not. The 1938, 1939, 1940 and 1941 pennies, as well as the Melbourne and Perth issues of the coins in the table above, were all struck with dies made from the same master tools so it would be quite reasonable to assert that they were just varieties of the same coin. With such an arrangement the table above would more properly be:

Another possible taxonomy for the 1942 and 1943 pennies

Denomination Penny Penny Penny Penny Penny Penny Penny
Obverse master die 3 3 3 4 4 4 4
Reverse master die D D D E E E F
Year 1942 1943 1943 1942 1942 1943 1943
Mint Perth Melbourne Perth Bombay Bombay Bombay Bombay
Variety I mint mark No I
Designator P3D-42-P P3D-43-M P3D-43-P P4E-42-B-1 P4E-42-B-2 P4E-43-B P4F-43-B

My feeling is that whereas technically the second table is more accurate in that it better describes the relationships between similar coins, it is so far removed from real-world usage that it is unlikely to be so useful.

Although the analogy with the evolutionary system of biological taxonomy is fairly strong, it is by no means perfect. One could consider the mint to be a top-level taxon and all coins as products of a particular mint. The argument for doing that is fairly weak but the fact that it is possible to arrange taxa that way is a reflection of fundamental differences between the way that coins and organisms developed. The point of this is that we don't need to get too carried away with accuracy in the ordering of taxa. All we need is a system which is logical, and above all, useful. We could start with the first arrangement shown above and move the "mint" taxon up a bit ...

Yet another possible taxonomy for the 1942 and 1943 pennies

Denomination Penny Penny Penny Penny Penny Penny Penny
Year 1942 1942 1942 1943 1943 1943 1943
Mint Perth Bombay Bombay Melbourne Perth Bombay Bombay
Obverse master die 3 4 4 3 3 4 4
Reverse master die D E E D D E F
Variety I mint mark No I
Designator P42P.3D P42B.4E.1 P42B.4E.2 P43M.3D P43P.3D P43B.4E P43B.4F

This is again less accurate than the second table but it is probably the most useful because it yields designators which most closely resemble the informal coding schemes in general use and which are most easily read. It is this sytem which I propose to use but I want to stress that I am open to argument on the issue. I am not trying to dictate to the numismatic community; I am trying to build something which will suit the everyone with the minimum of adjustment.

The coding scheme

I have given a hint of the shorthand notation in the tables.

Following John Dean's system, the first letter signifies the denomination:

  • H - halfpenny
  • P - penny
  • T - threepence
  • X - sixpence
  • S - shilling
  • F - florin
  • C - crown

Because sixpence and shilling start with the same letter, I chose X to represent sixpence, that being the second most significant letter in the word. (John Dean resolved the conflict differently, using Sh to represent shilling.)

Following the denomination is a two-digit year so H31 means 1931 halfpenny, S62 is a 1962 shilling.

Next comes the mint.

Mint codes

  • L - Royal Mint, London
  • H - Heaton & Son, Birmingham
  • C - Calcutta branch of the Royal Mint
  • M - Melbourne branch of the Royal Mint
  • S - Sydney branch of the Royal Mint
  • P - Perth branch of the Royal Mint
  • B - Bombay branch of the Royal Mint
  • F - U.S. Mint, San Francisco
  • D - U.S. Mint, Denver

Note that common usage has S as San Francisco because of the mint mark. There should be no confusion if S is used for both Sydney and San Francisco because the Sydney mint closed in 1927, long before any Australian coins were minted in the U.S.A.. Another common usage is the letter I to denote either of the Indian branch mints. While not as precise as using B or C, no confusion should arise because Australian coins were not minted at Calcutta and Bombay in the same year.

So far we have T42M, T42F and T42D for 1942 threepences minted in Melbourne, San Fransisco and Denver respectively. I expect that frequently T42S will be used in lieu of T42F.

It is rarely possible to distinguish between Sydney and Melbourne mintings in the twenties. To use X23M and X23S for the 1923 sixpences implies more than can be discerned from the coins. Nevertheless while something like X23M/S would be accurate, I expect most people will use X23M to serve for both mints. (Of course for the previous year X22S is correct and X22M is wrong because all 1922 sixpences were minted in Sydney.)

Next comes the master die number and letter for the obverse and reverse respectively. I put a dot either side of this to separate it from the other components. The die numbers and letters are patterned after Paul Holland's scheme for the halfpennies. Each die is given a unique number or letter. This represents a bit of a departure from the "ease-of-use" ideal because the numbers and letters don't have any obvious meaning. It is a compromise that I accept because I anticipate that in common usage most people will drop the die designators altogether and those people who are interested will soon remember them. At most there are nine obverse and reverse dies for any given denomination so that isn't too much to bear.

To this point we have something like F11L.2A for the 1911 florin. The F is the denomination, 11 is the year, L signifies the Royal Mint in London, 2 represents the second obverse die for the denomination (the first being the Edward VII obverse of 1910) and A represents the reverse die.

Finally we have the variety. Unfortunately I have not been able to devise a systematic way of describing those and the attempt may prove to be futile. Fortunately, with the taxonomic heirarchy developed this far, most varieties are already identified without additional notation.

I am open to suggestions but for the moment I cannot think of any system better than numbering the varieties or adding a short English description.

Now for a dose of reality. I suspect that most people will simply ignore the master die designators so that F15L.2A and F15H.2A will become F15L and F15H respectively. That is still a useful code, especially since the master dies are the same anyway. When dies become important then the designators can be included. P43B.4E and P43B.4F completely define the two varieties of the 1943 Bombay penny with no additional description.

Some irregularities

Unfortunately not all of the Australian Commonwealth coinage fits comfortably within the nomenclature. For a start, we have the four commemorative florins issued in 1927, 1934, 1951 and 1954. Whereas I have accommodated them within the nomenclature by defining master die designators where appropriate, I wonder if that is really the best thing to do. In a sense these florins are quite separate from the standard issue coins and maybe they should have their own classification.

Another difficulty arises with a few coins which were produced at the Melbourne mint, some with a mint mark and some without. The 1921 threepence is the obvious example. Popular shorthand has "1923M" and 1923 plain" for the varieties with and without a mint mark respectively. According to my proposed nomenclature these should both be T23M.2A with with a variety designator appended, e.g. T21M.2A.1 and T21M.2A.2. The difficulty here should be obvious. Who is going to remember which of .1 or .2 means the mint mark? A coding scheme designed to facilitate the distinction between varieties is actually making matters worse.

The problem could be solved by inventing something better than a numeric suffix for variety designators. T23M.2A.M and T23M.2A.plain would be much more descriptive. I'm asking for help here.


The foregoing scheme was developed for my own use but I am submitting it to the Australian numismatic community for consideration and criticism in the hope that it might actually be useful to other people.

The taxonomy is designed for the Commonwealth coinage of Australia only. I have not attempted to extend the scheme to other numismatic arenas, and in particular to Australian decimal coinage. That would be a challenge and I suspect a somewhat different scheme would be needed to cater for circulation coinage and for the bewildering array of collector issues being produced by the mints in Canberra and Perth.

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