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This letter contains money intended for the Russian Andreevski monastery at Mont Athos, but instead of being routed to Odessa, it is routed to Rostov on Don - the only example of this routing that I have. My assumption is that there was a collection point in Rostov like the one in Odessa.
It definitely started out in Kherson. There are four small private seals and then a large central seal which is that of the Kherson post office - it's readable. Around the seal are three strikes of Kherson cancellations dated 25, 26 and 28 November - the cancellations in two different styles: just look at the base fleurons. Calculations at the left of the seal (upside down on the scan) show an addition of 90 kop + 6 roubles + 5 kop = 6 roubles 95 kop so not exactly a big money letter. [But seee Howard Weinert's Comments posted below]
Finally, the letter was on its way and there at the bottom is a cancellation reading ROSTOV ON DON / 2 DEKA 74. But this cancellation is simply not in any recognisable Imperial post office style. So what is it? Could it be a cachet used by the receiving ecclesiastical organisation in Rostov?
Then at the top in a different blue - grey ink is a mark of some control office KONTROLNAYAR PALATA and a date IX 74. It is unclear whether this control mark is under the post office seal or over it. The date is deeply unhelpful. Maybe the IX is an inverted XI, in which case this mark was applied before the Kherson post office seal in November. But where was the Control Office which applied this mark? [See Arno's Comments published below]
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