I’m not sure, and I don’t recall there being a scale, either. Appears to be carved, but into what, and vertical or horz surface I dunno.
Figure 1: One of the satellite photographs clearly showing the vast amount of inscriptive material discovered by Archaeoastronomer, William James Veall, on the South Atlantic coastline of Uruguay, South America. (Copyright William J Veall 2014)
A satellite photo it says, must be of sufficient size
for that kind of resolution...