Study of a rock-face

I was recently in Nuremberg and had been keen to see the Albrecht Dürer house, although I was a bit disappointed to be honest, hoping for something that felt a bit older and less-restored. You can see the city's castle from Dürer's upstairs windows, just the other side of a square, with walls made of distinctive red sandstone. Inside the castle they have a reproduction of the sketch above and a text explaining that this particular sandstone was laid down about 215 million years ago. 'Albrecht Dürer painted sandstone formations at rock quarries in the Nuremberg region. These rocks are still used for restoration work at the imperial castle, the Peller courtyard, or the structures at the zoo. The last quarry still in operation for Nuremberg sandstone is the one in the Lorenz Reichswald Forest.' I've uploaded a photograph from Wikimedia of this Steinbruch Worzeldorf quarry below:

Source: Derzno 

The Dürer sketch is in the British Museum and you can zoom in on it at their website to look at the details of the rocks. The BM curators say that 'he would have referred to drawings such as these when he designed the detailed rock-face in the background of his engraving, St Jerome in Penitence of about 1496-7.' The reason this is inconsistent with the 1506 date is that they think the monogram was added by a later admirer. I've reproduced the Met's copy of the St Jerome engraving below. In London we have the National Gallery's Dürer painting of St. Jerome, which has some reddish rock formations and the kind of trees the saint would have seen if his wilderness had been somewhere near Nuremberg rather than the Syrian desert.