▶ Your Answer :
The reading passage contends that the origin of the forts built with stones that are vitrified can be explained by three theories. On the other hand, the lecturer makes a counterargument with several points. First, the writer acclaims that vitrification was attributed to signal fires. The continual heat from fires would have melted the rock over time. In contrast, the professor contends that if forts had used to signal fires, only a few walls of the those would have been affected from fire. However, the entire area of the upper part of the forts are vitrified. Second, according to the reading, lightning might cause the stones vitrified. The intense heat by lightning strike is sufficient to make rock vitrified. However, the lecturer maintains that the forts are so large that the numerous individual lightning would have been required to be the cause of vitrifaction. Furthermore, it was nearly impossible for that many lightning to strike one place. Poor condition of the wall can be illuminated by the fact that the forts are so old that it is natural result. This counters the writer’s claim that lightning accounts for uneven appearance. Finally, the author said that some researchers have suggested that forts were built using volcanic rock. On the contrary, the lecturer contend that there were no path of the volcanic eruption near the forts. Because they could not transport heavy materials, they would have used ingredients that were close to them. |