Stop 12
Figure 12a

Continue south on Gay Street past Water Street. Turn west (right) on East Lombard Street and walk about one block This last stop is at two stone sculptures on East Lombard Street just short of Commerce Street.

The first stone sculpture (Figure 12a) is a light and dark gray limestone. The light gray portion is calcite and the dark material is dolomite (Figure 12b). As with many limestones, this rock was formed in shallow, quiet seawater and contains evidence of fossils, perhaps algal mats. The stone is Cambrian in age (about 550 million years old) and was quarried in Tennessee.

Stop 12
Figure 12b

The other stone sculpture (Figures 12c and 12d) is a light gray and pink limestone also from Tennessee, but is Ordovician in age (about 470 million years old). This limestone contains irregular contacts called stylolites that probably formed by differential solution and compaction or “settling” when the sediments were still relatively soft. Stylolites resemble the pen markings on a seismograph or an EKG (electrocardiogram).

Stop 12
Figure 12c

To return to Stop 1 from the corner of Lombard and Commerce Streets, turn south (left) onto Commerce Street and walk one block to Pratt Street. (The harbor is on the opposite side of Pratt Street.) Stop 1, The Gallery, is two blocks to the west (right) at the corner of Pratt and Calvert Streets.

We hope you have enjoyed this tour and learned to recognize some of the more common building stones in downtown Baltimore. You may recognize these same building stones in many other parts of the city. For additional information on the geology of Maryland, you are invited to contact Dale Shelton at Maryland Geological Survey at (410) 554-5500 or visit the Survey between 8:30 a.m. and 4:30 p.m., Monday through Friday at 2300 Saint Paul Street, about two miles north of downtown Baltimore.

Stop 12
Figure 12d