This is the cornice above the large shaft supporting the Southern Portico, nearest to the Porta della Carta, Shaft A or the Carta Shaft. Discussed at Notebook M p.201 as ‘Carta shaft or A’.
Notebook M p.180L ‘Measures of shaft A’
Notebook M2 p.190 Index ‘Carta Shaft St Notebook M p.3’
[Version 0.05: May 2008]