344 HATCHER MARINE AND NON-MARINE FORMATIONS. [April 7, 



are receiving vast quantities of material from the numerous streams 

 emptying into them and are destined at some future time to be 

 converted into fresh-water swamps like those now found inland, 

 while the coast will be pushed farther eastward, repeating the same 

 or very similar conditions. 



If now we examine the material that is being deposited at vari- 

 ous localities, commencing with that point on the coastal plain 

 where deposition is more rapid than erosion, and extending east- 

 ward not only to the coast line but beyond to the eastern border of 

 the continental plateau, we shall find that deposits of every charac- 

 ter, from fresh v/ater to estuary or brackish, littoral and purely 

 marine, are being formed simultaneously, in each of which are pre- 

 served remains of the life characteristic of the conditions attend- 

 ing its deposition. In the s'.vamps will be found peat bogs and 

 beds of sand, clay and marl, with remains of terrestrial and fresh 

 water vertebrates and invertebrates. Over the river bottoms will 

 be found fluviatile deposits. In the estuaries, bays and sounds 

 beds with the remains of a brackish water fauna are forming. Out- 

 side the sand spies that enclose Albemarle and Pamlico Sounds will 

 be found other beds of sand with a littoral fauna. Still farther sea- 

 ward and continuing to the limits of the submerged continental 

 plateau a typically marine deposit is being laid down with remains 

 of its characteristic fauna. Beyond this we reach the abysmal 

 depths of the ocean with a fauna and deposit distinct from any of 

 the others mentioned. Assuming that the average depth of the 

 ocean just west of the eastern border of the continental plateau is 

 3000 feet, and that the western limit of true marine conditions 

 extends to within fifty miles of the eastern limit of true fresh water 

 or terrestrial conditions, we have then. within a distance of fifty 

 miles from east to west every character of deposit from terrestrial 

 and fresh water to true marine forming at the same time; and if we 

 continue our section to the eastern limit of the continental plateau, 

 at altitudes differing more than 3000 feet from one another, as indi- 

 cated by the curved line a. a', which in the accompanying diagram, 

 seen in figure i, represents an imaginary line drawn along the 

 surface of the ground and bottom of the sea from the western bor- 

 der of the swamps lying west of Pamlico Sound in North Carolina, 

 across this sound and eastward to the eastern border of the conti- 

 nental plateau. Along this line a. to b. is the swamp region with 

 fresh water deposits, b. to c. Pamlico Sound with its estuary depos- 



