" The conventional wisdom during the early part of the century was that these pisoliths were formed by the action of algae growing over the surface of fine grains. The grains became larger as the algae facilitated chemical precipitation of lime (calcium carbonate) and/or the capture of fine sediments. As the grains were rolled around by moving water, growth would take place on all sides producing a somewhat spherical pisolith."
Means life or water?...
Water, possibly, life, not necessarily.
http://www.grisda.org/origins/23110.htm "The most dramatic change in thinking about the origin of these spheres took place just a few years later when two investigators, Robert Dunham6 and Carroll Thomas,7 working independently, concluded that the pisoliths were not the result of the work of algae, but were formed inorganically, underground, by the gradual accumulation of their many lime layers (Figure 2) around an original nucleus. As water occasionally percolated down through the normally dry soil of the region it facilitated the replacement of the original lime sediments with layers of denser concentration which form the pisoliths. The common spherical concretions we find in many sedimentary rocks are thought to have formed in a similar way."