1898] MARYI.AND ACADEMY OF SCIENCES. 395 



PRELIMINARY NOTICE OF A RECENT SERIES OF GEO- 

 LOGICAL ACCUMULATIONS, THE McHENRY 

 FORMATION. 



By p. R. UHLER. 



On various occasions within the past twenty-five years, 

 specimens of wood, leaves of modern trees, bark, seeds 

 and other deposited. materials have been brought from the 

 black bogs and next overlying beds of the Patapsco region 

 for examination, identification and discussion. My inves- 

 tigations of these deposits, their contents and relations have 

 brought out the following facts and inferences. 



This series of marshes and beds constitutes one of the 

 latest formations of the Modern Period. It extends over 

 parts of the recent beaches of the Patapsco river and 

 Chesapeake bay, and near Baldmore composes the upper 

 part of the Fort McHenry plateau, in the marsh of which 

 the Bald Cypress, Taxodium distichum Rich, and the com- 

 mon White Cedar, Chamcecypavis sphceroidea Spach. form- 

 erly grew. Stumps of these trees were numerous in the 

 black mud which underlies the black, the drab and the 

 3'-ellow clays capped by the upper sands and gravels of 

 the shores of Whetstone Point in the harbor of Baldmore, 

 occurring also on the West Branch of the Patapsco river 

 adjoining the lands of the United States government at 

 Fort McHenry, and the continuation of these shores to- 

 wards Winan's Cove, as well as farther back under the 

 beds of Eutaw and Howard streets to near West street. 



The formadon varies greatly in thickness and where 

 complete condnues up from the black marsh, or marshy 

 sand, deposited in the depressions of the cretaceous clays. 

 Probably the thickest series of beds of this formation, 

 which has recendy been exposed to examinadon, is that 

 where the sewer was dug beneath Eutaw street, south of 

 West street. Omitdng the 5 to 8 feet of gravel, sand and 

 soil of the surface, the total thickness is 23 feet. The 



November 19. 



