Obverse features:

1.1 Almond-shaped eye without eyelids
1.2 Almond-shaped eye with lower lid
1.3 Wishbone-shaped eyelids
1.4 Round eye with line through pupil
1.5 Round eye without line through pupil

2.1 Naturalistic nose
2.2 Similar to "Class IV" nose
2.3 Anchor-shaped nose

3.1 Mouth ornament
3.2 No mouth ornament

4.1 Linear neck truncation
4.2 Beaded neck truncation

5.1 Hair forms back of neck
5.2 Linear back of neck

6.1 Almond-shaped eye without eyelids
6.2 Almond-shaped eye with lower lid
6.3 Wishbone-shaped eyelids
6.4 Round eye with line through pupil
6.5 Round eye without line through pupil

7.1 Normal neck front
7.2 Curl at front of neck
7.3 Neck curves to mouth ornament

Reverse features:

8.1 "Class I" pony with bead for eye
8.2 As above, but with notched cheek section
8.3 "Sea horse" headed pony with wavy tail

9.1 No martingale in front of pony's chest
9.2 Martingale in front of pony's chest

10.1 "Fan" driver with hand
10.2 "Fan" driver with segmented body
10.3 "Weird" drivers
10.4 Driver as 10.2 but with cheek section
10.5 "Fan" driver with no hand

11.1 Quadrilateral banner
11.2 Curl and leaf banner (one or two)
11.3 Curl and quadrilateral banner

12.1 Two strand lash with X's
12.2 One or two strand lash with no X's
12.3 Three strand lash

13.1 Lash touches head above pony
13.2 Lash not touching head above pony
13.3 Lash to mane ornament
13.4 Lash to driver's head

14.1 Pony without ears
14.2 Downward pointing ears
14.3 "Naturalistic" ears
14.4 "3"-shaped ears
14.5 Laurel-leaf shaped ears

The coins of these classes, which form Series Y, are very different from the preceding classes of Series X: there is no indication that they were designed or manufactured by the same individuals who produced the previous series. The coins of Series Y generally exhibit higher relief, and were struck at a temperature greater than those of Series X (Classes VI to IV), often resulting in coins with small irregular cracks and porosity on the edge. These faults were caused during the minting, the surface having already cooled to produce a "skin," while the interior was still plastic. It is possible that the die engravers cut the dies rather deeply, and then found, when striking them at ordinary temperatures, that the higher parts of the design failed to strike up properly; however, it is more likely that this method was just part of a different manufacturing tradition.

The die engravers of Series X may have simply decided to break with their earlier traditions and embark on something quite different, but this hypothesis fails when we examine the different distribution patterns, as was discussed in Chapter 2, and when the nature of the changes that occur in Series Y are examined thoroughly. There is a completely different psychology operating here: in the previous series, the changes are gradual and evolutionary, and marked by a more or less complete abandonment of certain design elements, followed by a trial and error effort to replace those rejected elements with something more satisfactory. In this series, containing Classes I and III, the intention is the same, but the results often fall short, leaving the die engraver no alternative but to return to the design element he was trying to replace.

This latter result made my chronological arrangement of the classes most difficult: I find it amusing, now, to recall that it was this series I first tried to put into some sort of order. I made many attempts to arrange these coins by grouping together similar major elements, such as the designs of the banners in front of the pony. All of these efforts failed miserably, and it was not until I noticed that the design of the pony's ears on some coins of Classes III were of two major varieties that the nature of the arrangement began to present itself.

The relationship of groups to classes:

Class I: Groups H, H1, H2, I

Class I/III transition: Group J

Class III: Groups K, L, M1, M2.