Research: Google searches for "weight of stone statues" and suchlike; Wikipedia articles on the Moai monoliths on Easter Island and the Chinese Terra Cotta Army.
Additional setting details: Humans have occupied this continent for several hundred years, and in the course of their conquest, they have discovered devices they call "heirlooms." The heirloom is a stone statue approximately 5 meters high (16.5 feet). The heirlooms are static if left alone, and are often found standing in regular ranks and formations, not unlike very large versions of the Chinese terra cotta warriors. Some humans have the capacity to make an heirloom move about - they can direct its movements by climbing into a compartment set inside the heirloom's torso.
Question: I need to move one of these heirlooms from one place to another within a city not unlike New York City in the 1870s. There has been a breach in the seawall, and significant flooding threatens the lower elevations of the city. The heirlooms are heavy enough that I don't want one tramping through the streets, as it'd tear up the cobblestone streets and probably damage buildings. I had originally thought to have a dirigible airlift the thing from one end of the city to the other, but it's also far too heavy for that to be plausible. My best bet is to put it on a barge, either laying down flat or sitting upright, and floating it downriver and to the repair site.
About how much would a 15-foot high, person-shaped stone statue weigh? I'm sure figures would vary wildly based on the kind of stone it is, but all I'm really looking for is a ballpark figure, something for a knowledgeable character to throw out there in dialogue.
The article on the Easter Island monolith indicates a certain 10 meter high moai weighs 270 tonnes (33 feet high and just shy of 300 tons), but I have no idea if that moai's proportions are an appropriate standard to use for guesstimating my 5-meter high heirloom.
I appreciate your help
Edited to add: Thank you all for your helpful comments! I think I know where to continue my research.