We are now presented with a page detailing the prior chronological information
for Layer III. We would like to change the relative chronological
information so that Layer III is earlier than Layer II rather than earlier
and abutting. In other words, we wish to test the effect of modelling
a hiatus between the layers, rather than modelling them as abutting.
To do this we simply select the radio button corresponding to "earlier".
The radio button that corresponds to "abutting earlier" is automatically