A FOSSIL CYPRESS SWAMP IN MARYLAND.* 



By Arthur Bibbins. 



ON the western shore of the Chesapeake, immediately south of 

 Stony Point, or about one and a half miles south of Bodkin 

 Point, a deposit of fossil Cypresses of large dimensions has 

 lately been brought to notice. It lies at the base of the Rar- 

 itan formation, at its contact with the recently defined Patapsco 

 formation (both Lower Cretaceous), where it has been exposed to 

 view by the action of the waves in wearing away the Bay cliffs. 



The deposit is made up of more or less loosely bedded materials, 

 including the prostrate trunks and limbs of Cypresses and other trees, 

 imbedded in "moss," broken and charred twigs, etc., and of large 

 Cypress stumps standing erect with their roots and knees in place. 



The Cypresses are in a surprisingly perfect state of preservation 

 as porous but tough brown lignite. A number of the stumps are at 

 this date standing in place upon the beach, partly submerged, and 

 fully exposed to the violence of the surf and the action of shore ice. 

 Judging by their distance from the receding cliffs, we may suppose 

 they have been resisting these corrosive agencies for a period of at 

 least ten years, yet their present condition warrants the belief that 

 they will persist for as many years to come. 



This excellent state of preservation is certainly not accounted for 

 by the great durability of Cypress wood itself, for it must be remem- 

 bered that the age of the Lower Cretaceous deposits is reckoned in 

 millions of years. An examination of the underlying and overlying 

 materials suggests that the Cypress bed was originally sealed up in 

 impervious envelopes of clay. At its base, penetrated by the roots 

 and rootlets of the fossil trees, is a compact, greenish, sandy clay con- 

 taining nodules of earthy carbonate of iron. The Cypress bed is 

 overlain by a similar stratum of clay, and this by several feet of very 

 fine soft blue clay. These overlying and underlying clays are seen to 

 blend at the lower (southern) limit of the Cypress bed, so that before 

 it was opened by wave action along its bayward margin the deposit 

 may have been hermetically sealed. 



The bed is now kept saturated by the water of the Bay, which, 

 during extreme high tides or the prevalence of heavy surf, penetrates 

 its porous materials to a considerable distance landward. The well- 

 marked saline ingredients of the Bay water at this point rendering it 

 congenial to barnacles, oysters, tunicates, crenophores and oceanic 



Published by permission of the Maryland Geological Survey. 



