102 The American Geologist. August, ii)oi 
surface would fringe the entire Atlantic and bay shore as well 
as that of the estuaries. The sea cliff would at first be sharp 
and easily distinguished, but as ages passed the less conspicu- 
ous portions would gradually yield to the leveling influences 
of erosion, such as soil creep, plant roots, cultivation etc., and 
might finally disappear altogether. Erosion would also destroy 
in a large measure the continuity of the formation, but as long 
as portions of it remained the old surface could be reconstruct- 
ed and the history of its origin determined. 
It was with these features well in mind that the author 
undertook the investigation of the surficial deposits in Mary- 
land, and it was found that they supplied the necessar}^ clue to 
their interpretation. Without entering into many detail.^ it 
may be briefly stated that the oldest terrace, the Lafayette, is 
found as outliers on the eastern edge of the .Piedmont plateau 
from Washington across Maryland and Pennsylvania to New 
Jersey. The elevation of these deposits varies from about 500 
feet behind Washington, as determined by Mr. Darton, to about 
300 or 400 feet in the vicinity of Philadelphia, where it has 
long been known as the Bryn Mawr gravel. Besides these 
outliers of the Lafayette on the Piedmont plateau, there are 
others on Elk Xeck occupying a lower elevation, and still an- 
other and more extensive area on the Coastal Plain immedi- 
ately southeast of Washington. This area has already been 
reported by Mr. Darton, but it has been found after careful in- 
vestigation that in place of extending down the peninsula to 
the Chesapeake bay, it ends in an abrupt low scarp line, which 
may be seen in the vicinity of Charlotte Hall, in St. Mary's 
county, and at numerous other localities. No Lafayette is 
known to exist, however, on the peninsula at Calvert county. 
The elevation of the Lafayette at this scarp in southern Mary- 
land is about 270 feet. 
The next younger formation, the Sunderland, is extensively 
developed throughout Prince George's, Charles, St. Mary's and 
Calvert counties, and numerous outliers exist on other parts of 
the Vtfestern shore from Herring Bay tO' Elkton, but the con- 
tinuity of the formation in this portion of the state has been 
destroyed. This formation is developed as an unmistakable 
terrace butting up against the Piedmont plateau or lapping 
around the edges of the Lafayette. The scarp line at Charlotte 
Hall is part of the ancient sea-cliff of the Sunderland sea. 
