2 adjectives to describe saxum

As I got further into Virgil and Clelia, I found myself transported from Arcadia to the garden of Italy; and saw Windsor Castle in no other view than the Capitoli immobile saxum.' Horace Walpole's humble friend Assheton was another of those Etonians who were plodding on to independence, whilst he, set forward by fortune and interest, was accomplishing reputation.

Intacti maneant, maneant per sæcula dulces COWLEII cineres, serventque immobile saxum.

2 adjectives to describe  saxum