Here is a registered cover sent from Ibadan on August 14, 1906, after Amalgamation, to Holsheim, Germany. There is a U.K. transit backstamp dated September 3 1906, but no arrival backstamp in Germany. The postage paid is 2/3d over the 2d value of the envelope, for a total of 2/5d. This has been paid with chalky paper examples of the 1/2d, 1d, and 2.5d and ordinary paper examples of the 2d, 3d and 6d.
The next scan shows the back of the envelope:
Note how the indicta on the back of the envelope is Lagos.
The next scans show a Sou…