I looked all over for a date and got everything from “early 1800s” to “late 1800s” but nothing exact, so I had to make an educated guess. The first cameras practical enough to take such a photo were developed around 1840 and the excavations began in 1867.
4 points
*
Maybe, between two excavations, the wind has partly filled up the cavity of the previous excavation with sand and thus, the progress wasn’t continuous.
This is supposedly from 1867 - 1878:
Wikimedia Commons
