REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1903 63 



which case the marl usualh^ predominates in the lower strata and 

 the peat in the upper strata. 



Clay. The deposits of clay that underlie many swamps are of 

 great value when accompanied by marl, with which it is mixed to 

 make Piortland cement. 



Infusorial earth. In the open waters near the center of many 

 bogs certain low grade plants and animals called diatoms and 

 infusoriae respectively develop and add their remains to the bog 

 accumulations. These plants and animals are composed largely 

 of silica, and the remains form a deposit that is known by the 

 various names of tripoli, infus'orial earth and diatomaceous earth. 

 Only two deposits of this material are known in this State, i. e., 

 at White lake, Herkimer co.. and Cold Spriug Harbor, L. I., but 

 careful prospecting will probably reveal other deposits in some 

 of the large marshes. The principal purposes for which this 

 material is employed are for heat insulation, metal polish and 

 the manufacture of dynamite. 



Bog iron ore. Another material that is likely to escape notice 

 in ordinary prospecting is bog iron ore, which is found in many 

 swamps just below the peat near the margin of the bog. Tlie 

 abundance of large supplies of better grades of iron ore prevent 

 exploitation of these deposits, though many blast furnaces in 

 Europe depend on this kind of ore for their supply. Many 

 swamps in the Adirondacks contain large deposits of this material, 

 and this seems to be the best locality in the State in which to look 

 for this material, though it may be found in the swamps elsewhere. 



PART 4 



Distribution of swamps in New York State 

 With but few exceptions the large swamps are in those parts of 

 the State that are approximately level. The salt maTshes are 

 found on the shores of Long Island, Staten Island, Manhattan 

 Island and that part of Westchester county bordering on Long 

 Island sound and the Harlem river, and the shores of the Hudson 

 as far north as Newburg. A list of the marshes on Long Island 

 and that part of Westchester county bordering on Long Island 



