It look like Lapiez (a kind of limstone dissolution)

Thanks Mark Keiter. Please be aware that I raised the question because the prints are not like any other present in these layers. They are important, as you can see from the picture, just like you have the bioturbation common on these layers.

I can not believe that these lines can be of animal origin but are regarded as how regular and mutually perpendicular are, I think that is too difficult for fingerprints generated by desiccation.

If there is a convincing model doubts remain.

Thanks Smaine Chellat for your contribution. I believe, however, that it is not limestone dissolution because the grid is too smooth, made up of lines that intersect perpendicularly.

Dear Mark Keiter, not far from this boulder I have found another in which the lines are quite perpendicular and in this it is evident that it is fracture lines, also because they are in part filled by a veil of calcite and because they affect more superimposed layers. Of course in the second boulder lines they are less regular. I am also convinced that the rock must first be a form of fault lines or, rather, of lines generated by a drying occurred before lithogenesis. Therefore it would treat of fossil footprints from desiccation and not of fractures after the lithogenesis. In your opinion, could this be the explanation?

OK Mark, it could be. Just directly back to Alba I'll do more research and read all the notes to the geological map.

Mark Keiter , you were right, the lines have a positive relief. It is the underside of the layer.