398 TRANSACTIONS OF THE 



their tissues and giving to them a brown color and tough 

 texture related to lignite. The specimens from localties in 

 South Baltimore have not been changed in this manner, 

 but have almost retained their color, while they have 

 gained much in flexibility. Those, however, which have 

 been dug out of the astringent, muddy clay of the Fort 

 McHenry plateaux were brown and contracted like those 

 from the bay below Bodkin Point. Through the kind- 

 ness of Colonel Craighill, specimens of all the kinds of 

 residual material and wood, dug or dredged from the mud 

 and clay of the Fort McHenry border of the river, have 

 been given to the Maryland Academy of Sciences, and I 

 have thus been enabled to give them a close and compara- 

 tive examination. The broad depression of surface which 

 still exists next the cove at the foot of Howard street, has 

 a considerable part of the surface uncovered, and in this 

 noxious marsh may still be found the stumps of Cypress 

 and Willow which grew in that region less than one 

 hundred years ago. 



These remnants of a formerly more extended series of 

 marsh deposits along the borders of the estuaries and 

 bayed out coasts of the Western Shore of Chesapeake 

 Bay are mostly restricted to troughs and shallow basins 

 of lowland drainage. These areas were lower than the 

 adjacent land, and were made so by the strong tides 

 backing inward the water of the branches, causing over- 

 flows and eddies which in time of storms eroded the banks 

 of the drains and carried out the disintegrated materials 

 into the estuary of the river. This work of the tides has 

 been almost brought to a close by the filling up of the 

 Patapsco river, although it still keeps on along the shores 

 of Chesapeake Bay, if not along the broad mouths of 

 large rivers, such as the Patuxent and Potomac. 



We are now beginning to find that some of the time 

 estimates of the Quaternary period have been too long, 



