Detail of entablature now in the Capitoline Museums.
This image shows the difference in depth between between the roughed-out section, the guideline strip, and the final surface. The roughed-out section sits about 4 cm proud of the finished surface while the guideline strip sits about 2 cm proud and 2 cm down. This strip, then, was supposed to act as a reference point for the layout of the fasciae and not their final depth or positioning.
