EXTINCT OCEAN-LIVING MAMMALS FROM MARYLAND 



Rv REMINGTON KELLOGG, 

 Assisfaitt Ciiratcr. Division of ^fa^lnJlaIs, U. S. National Mhsckiii 



During Middle Miocene times a cnnsideralile portion of southern 

 Maryland was submerged l)elow sea level and an extensive estuary 

 of the sea reached northward across the state. Conditions were 

 favorable for the deposition of sediments such as clays and sands, as 

 well as for the existence of large iuiml)ers of ocean-inhabiting animals. 

 These animals lived and died, and their hard parts or skeletons found 

 a resting place on the sandy bottoms where in the course of time 

 they were buried l)y successive layers of sediments. Then conditions 

 changed and much of this area was uplifted above the sea. Many of 

 the animals that frequented this region disappeared and new ones took 

 their places. And it is in these Calvert sands and clays that we are 

 able to reconstruct from more or less fragmentary remains the life 

 that existed there at the time this formation was being laid down. For 

 several seasons past, the writer and Mr. Norman H. Boss have been 

 engaged in searching the exposures of the Calvert formation in Mary- 

 land for remains of fossil pelagic mammals. These studies have been 

 continued in cooperation with the Carnegie Institution of Washington. 

 Sufficient material has been accumulated to determine the variety of 

 types that frequented the sea covering this area during Miocene times. 

 Additional material is still needed to interpret the structural peculiari- 

 ties of some of these extinct water-frequenting mammals. 



One cannot expect to find bones everywhere nor is it possible to 

 search the surface oi the entire formation, for much of it is buried 

 beneath later deposits of earth. Along the western shore of Chesa- 

 peake Bay is an almost unbroken exposure of sandv clay known as 

 the Calvert Cliffs, which extend southward from Chesapeake Beach 

 for a distance of nearly 30 miles and in places attain a height of 

 about 100 feet. The tides, the waves that rise in rough weather, and 

 the storms, singly or conjointly are constantly cutting away the face 

 of this cliff, exposing bones of animals that died and were buried in 

 the sandy clays that comprise the Calvert formation. The waves cut 

 away the foot of the cliff and thus undermine the exposed surface. 

 Large blocks of the overhanging face dro]) off and these " falls " are 

 soon washed away. In a relatively short time the bones that fall in 

 the water are damaged or destroyed. For this reason the cliff must 



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