Fossil plant or coral? East Lansing Michigan

[darrow]

Found by a friends kids in their backyard in East Lansing, Michigan.  Any ideas?

[TqB]

Tabulate coral, something like Aulopora.

There are also a couple of cross sections of rugose corallites on the left.

[abyssunder]

I agree.

 

 "The colonial tabulate Aulopora had a long geological history and mainly occupied an encrusting niche, coating brachiopods, stromatoporoids and other, larger corals.
Aulopora grew by dichotomous branching, pursuing a creeping or reptant life mode, efficiently siting its corallites adjacent to potential sources of food at, for example, the inhalant currents through brachiopod commissures. Colin Scrutton (University of Durham) has reconstructed colonies of the free-living animals in three dimensions using a computer-based technique (Fig. 11.28). Serial sections of the colony were digitized and assembled on a micro-VAX mainframe with software routinely used for building up three-dimensional views of diseased kidneys. Both the ontogeny of the procorallites and the astogeny of the colony as a whole were established in considerable detail by these techniques. With the development of desk and laptop microcomputers such modeling is now, more or less, routine. Halysitids were tabulate corals that dominated some Ordovician and Silurian assemblages. As each colony grew, budding chains were able to find their way back to the colony, instead of heading off in random directions. Perhaps they could sense the gradient of a diffusive field of “pheromones”, their waste products or the depletion of nutrients set up by the colony. In a simulation by Hammer (1998), new protocorallites are introduced into random positions, simulating “polyplanulate” astogenesis and the diffusive zones are established by numerically solving the differential equation for diffusion and decay. " - link to source

 

 Figure 11.28 Aulopora morphology: computer-generated reconstructions of (a) the plan, (b) the lower side, and (c) the direction of the procorallite; (d) reconstruction of the colony. (Courtesy of Colin Scrutton.)