White Watson’s treatise on the strata of Derbyshire was written 33 years after Whitehurst’s. The most striking feature of Watson’s work is certainly the very long fold out section of the entire width of Derbyshire, from Buxton to Bolsworth. Whitehurst’s toadstones appear in this section as the strata numbered XXVII, XXIX, and XXXI, and they are quite distinctive on the section, being printed in dark black with tiny white bladder-holes. The full section is displayed in the exhibit; the illustration here reproduces approximately the left half of the section.

Watson’s discussion in the text attempts to connect toadstone with igneous rock that is found elsewhere. He says that toadstone appears to be the same rock that is called whinstone in Scotland, and Mandelstein by the Germans, and it is quite similar to the lavas that have been brought back from Vesuvius. The origin of whinstone was being hotly debated by Scotish geologists, as we shall see (Section XV, below).