256 REPORT OF NATIONAL MUSEUM, 1904. 



limits of the secondary formations, which he found here to consist 

 mainly of limestone strongly resembling the mountain limestone of 

 Derbyshire in England, and he announced himself as "fully satisfied 

 that almost every fossil shell figured and described in the Petritica 

 Derbiensia of Martin " was to be met with throughout the great cal- 

 careous platform of the Mississippi Valley. The limits and character 

 of the "Ancient Marine Alluvium," its fossil and mineral contents 

 were discussed; the essay concluding with some observations on the 

 Transition Mountains of Arkansas, with brief notes on the hone slate 

 of Washita. 



In 1820 there appeared also H. H. Hayden's Geological Essays. 

 These are of especial interest as dealing particularly with the Tertiary 

 and more recent alluvial deposits of the Atlantic and Gulf coasts, form- 

 ing what is now known as the coastal plain. The work 

 "mo en ' s Essays ' is verbose in the extreme and more argumentative than 

 logical. Indeed, were it not for its historical interest 

 and for the light which is thrown upon the crudities of early observa- 

 tion and deduction, it would be scarcely worth considering at all. 



After referring to the geographical limits of this coastal plain, as 

 defined and mapped by Maclure, and combating the opinions of pre- 

 vious observers [including Latrobe, Stoddard, and others] to the effect 

 that it was formed by flood tides and the winds acting on materials 

 cast up by the sea or through the transporting powers of the great 

 rivers, Hayden proceeded to elaborate his own theories in a way as 

 ingenious as it now seems improbable. "Viewing the subject in all 

 its bearings, there is no circumstance that affords so strong evidence 

 of the cause of the formation (i. e., the coastal plain) as that of its 

 having been deposited by a general current, which at some unknown 

 period flowed impetuously across the whole continent of America, and 

 that from northeast to southwest." The course of this current he 

 assumed depended on that of the general current of the Atlantic 

 Ocean, the waters of which rose to such a height that "it overran its 

 ancient limits and spread desolation on its adjacent shores. 1 ' 



In seeking a cause for this general current the author referred, first, 

 to the seventh chapter of the book of Genesis, "For yet seven days, 

 and I will cause it to rain upon the earth forty days and forty nights, 

 and every living substance that I hav< made will I destroy from off the 

 face of the earth." He then proceeded to show the inadequacy of this 

 cause alone; the water being thus equally distributed over the ocean 

 and the land, there "could be no tendency to cause a current in the 

 former." Some other cause must therefore be sought, and fortu- 

 nately his imagination proved equal to the task. 



Accepting as probable the suggestion of "a writer of no common 

 celebrity," presumably Kirwan, to the effect that the cause of the 

 general deluge was the melting of the ice at the two poles of the earth, 



