This specimen is an odd geologic curiosity that was recovered from a karstic outcrop along Florida's Peace River. It is some kind of sandstone-like concretion. Specimens such as these have been known to scientists and geologists for a long time, and examples are found at scattered localities around the world. The exact composition, shape, and texture varies according to the local geology where the specimen was recovered. Local cultures have called them different names, including : sand dolls, earth dolls, cave dolls, loess dolls, solder dolls, and weld dolls. Some of the most well-known examples were documented from the Cinquantamila cave in Italy (where they are known as "bambole del saldame").
The prevailing theory about how these are formed is that they are concretions that are formed in quartz-rich sand through dissolution processes, although the exact mechanism of action is unknown. There is still some debate and discussion going on in academic circles and you can find more information by searching the web for "Welded dolls and quartz sand deposits: a new line of research from the E. Boegan Caves Commission on the Trieste Karst". These anthropomorphic concretions are not common and they are only sporadically found. That fact has contributed to the lack of literature online about these oddities.
This example was recovered while hunting for fossils on Florida's Peace River. The spot where it was found also contained several similar specimens, but this is one of the only times I have encountered these concretions while search many miles of this river and many locations in central Florida. These specimens are more commonly found in areas with karstic geology and the Bone Valley Formation of the Peace River is one such area. This area is underlain with Hawthorn Group limestone with scattered chert nodules, sandstone, and fossil deposits.
Refer to the photos. The black scale cube and rule is not included. You are purchasing the specimen shown. It measures approx. 7 x 6 x 1 inches (175mm x 150mm x 25mm) and it has a flattish profile.
Note - I have a few more of these concretions, but this is the best "doll-like" example of the bunch. Contact me via email if you are a researcher interested in more examples.