Trench walls of cohesive rock are likely to remain intact when exposed, and the historical structures built of stone, mortar, and plaster provide evidence of workers from the past. Geologists may not get the same comprehensive geological history from cliff faces or road cuts as from undisturbed cross-sections.
Generally, trench walls of cohesive rock will remain intact while exposed. In the context of geology and the study of Earth's history, it is important to understand that different rock formations have varying levels of stability when exposed to elements such as weather. For instance, the twelfth- and thirteenth-century structures made of stone, mortar, and plaster are particularly durable, leaving behind evidence such as hand or fingerprints of the workers in the mortar and plaster. These historical imprints allow us to connect with the past.
On the other hand, when geologists rely on cliff faces or road cuts for geological history, the thoroughness of the geological record might be less accurate than studying an intact cross-section due to missing pieces or disturbed layers.
So, the integrity of an exposed trench wall greatly depends on the type of rock, with cohesive rock being more likely to remain intact. Understanding the stability of these rock formations is crucial when interpreting the geological history from exposed strata.