Given the missing attributes, the identification as Umamaheshwara is based on the presence of Ganesha on Siva’s right, the bull on which Siva is resting his right foot and the lion on which Uma/Parvati is resting her left foot. Siva and Uma with their sons, as in this bronze, is one of the common iconographies from the Pala period.
The other seated figure on Uma’s left is likely to be their other son, Skanda. Lack of attributes prevents positive identification. The figure at the base, on the right of the image, is likely to be the representation of the donor.
This bronze would have had a backplate. But time has taken its toll.
Notice the difference in the levels of vahanas, a bull and a lion. Natural depiction allows for the height difference between Siva and Parvati and the fact Parvati is sitting on Siva’s thigh and hence at an elevated level. It takes some thinking to do this.
Four deities, two vahanas and one donor. A complex piece of its size, it is about 8 cm in height. This bronze may date to the 10th or 11th century. It is from Eastern India (Bihar/Bengal)
Desire and Devotion Henry and Berthe Ford collection by Dr Pratapaditya Pal has an example of a similar piece, Catalogue item number 12.
Philadelphia Museum of Art has an example as well. Object number 1994-148-234.