C
I'm still not decided on the Ica stones. The Genesis Park website has this writeup which does seem to lend them credibility.
I think the stumbling block is, duplicates were forged for profit.
Other items of anatomical accuracy that attest to the authenticity of these Ica Stone depictions include the positioning of the tail and legs. Early critics said the Ica Stones were fakes, in part because their tails were sticking out while walking. Paleontologists in the 1960s were confident that dinosaurs dragged their tails. The paleontologists were wrong and the Ica Stones were right.
Scientists now believe dinosaurs held their massive tails off the ground while walking, because there are no drag marks on dinosaur trackways.
The dinosaurs on the Ica Stones are depicted standing upright, rather than with legs splayed out in a lizard-like position. That, according to dinosaur experts, is “dead on” accurate. The stylizing of animals depicted on the Ica Stones matches those found in the Nascan Lines (monkey with curled tail, hummingbird, and stylized dinosaur). Many of the Ica Stones were been blackened so that the artistic etchings stand out. While some fraudulent Ica Stones have been manufactured in recent years to sell to tourists, a number of the dinosaur stones were found in tomb excavations by experienced archaeologists. Moreover microscopic analysis of the patina (covering the stone surface) and oxidation in the etching grooves unambiguously distinguishes between the authentic and the recently forged artifacts.
I think the stumbling block is, duplicates were forged for profit.