The various analyses reported above show that the area of ground where the phenomenon is reported to have been
observed by Mr. Nicolai has indeed undergone certain alterations of a mechanical and thermal nature, as follows:
- Mechanical effects are exhibited in Figures 14 and 15 where one can see dark and light areas corresponding to
curved striations with precise groove-like contours. A piece of silex has been cut and it even appears to have been
superficially ground or polished. The dirt gathered at this particular spot is hardened, compacted and it exhibits a
crust which contrasts with the reference sample, which is loosely structured.
- Thermal effects produced by friction were noted by the SNEAP laboratory because the sandstone is found to be more
compact under the black iron (or iron oxyde) trace than at other locations. In addition, grains of` CO3Ca
are not "swarming." Hence they cannot have been heated up to more than 600 degrees C, a process which would have
dissociated, then recombined this compound. Furthermore the Rangueil laboratory failed to reproduce the observed
microcrystallisation by heating the sample to 1,000 degrees for two hours.
In summary, we find that a strong mechanical pressure, probably due to a shock, was exerted at the surface of the
"round." Superficial modification of the structure (striations and erosion) took place. A heating effect which may
have been caused by this shock, but which did not exceed 600 degrees, was subsequently observed. Foreign elements
consisting in a small quantity of iron (or iron oxyde) over a limestone grain, and a small but detectable amount of
phosphate and zinc were deposited at the site.