| The Canal Zone Study Group |
 |
 |
| Type III issues on cover |
 |
 |
| Pair of #46 second printing paying 2-cent domestic letter rate |
 |
| Single of #48 first printing paying the 5-cent foreign letter rate |
| The Canal Zone Study Group |
|
|
| Type III issues on cover |
|
|
| Pair of #46 second printing paying 2-cent domestic letter rate |
|
| Single of #48 first printing paying the 5-cent foreign letter rate |