Weathering of marble and limestone is another possible focal point of urban field trips. Have students feel the difference. Exterior sculptures and monuments will lose their finely-carved details. In order to help students make the connection between stone used for buildings and natural rock outcrops it is useful to find information on locally quarried building stone. If stone has been quarried in your area, find locations where that stone has been used, and obtain natural samples or take photographs of an outcrop of the rock for comparison.
Library research can reveal other useful information.
With the help of standard geological references one can find such information as the geologic age of specific building stones and the formal geologic names of rock units to which these stones belong. Basic Preparation for the Field Trip Pick buildings or other sites to be visited. Devise activity for each stop. Determine approximate amount of time needed for each stop. Get permissions if necessary.