This is the Saint Petersburg coat-of-arms used from 1730 to 1856, and depicts a red field with a vertical sceptre lying over a two-bladed sea anchor crossed with a four-bladed river anchor. The sceptre is crowned with the triple-crowned two-headed eagle of the Russian state.
According to the reference, in 1730 Anna Ioannovna approved this coat of arms with the four-bladed ship anchor, and in 1856 Alexander II, among other changes, ordered the anchor be replaced with the three-bladed ship anchor.
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