Maryland Department of Natural Resources

Stop 11: PARKING GARAGE - Gay Street

Backtrack west on Fayette Street to Gay Street and turn south (left). Walk south on Gay Street continuing ½ -block past Baltimore Street. Notice the parking garage on the west side of Gay Street. Can you guess the type of stone seen in this tan surface with the red base? This is a man-made “rock.”

A close examination will show that it is an artificial rock called an aggregate. An aggregate is a collection of pebbles, mixed with cement to form a solid man-made rock (Figure 11).

Stop 11
Figure 11