We believe this is either a sterling silver sherbet bowl or open ciborium from the late 19th / early 20th century.

It's labeled "I.S. Co.", for International Silver Company. International Silver was an American conglomerate that often used the marks of its subsidiaries; in this case, it features what appears to be the Eagle mark of the "Meriden Britannia Company" (which became part of I.S. in 1898). 

It needs to be polished slightly more, also the rims are a bit bent and it has some small dents