14 ULLETIN -V>. INITKD 8TATKS NATIONAL MUSEUM. 



ill Uiru'o nuinbors. Blue niiui appears on the line of this survey only 

 oti' the coasts of Luzon and Japan. 



(r/'t()i hunl. — Green mud is found under the same eonditions as blue 

 mud. It is said to oAve its color o'cnerally to the presence of the oli\e- 

 oreen mineral glaucouite. but sometimes to the presence of oro-anic 

 matter and its reducing- action upon iron peroxide. In some instances 

 the o-reeu color of the specimens has turned a bluish-black since 

 recovery, and from ])reseut appearances would be called blue mud. 

 In all the specimen-; of green mud the tinge of o-reen is faint, and the 

 greenish grains of sand comprise but a small part of the sediment. 

 A large part of the coloration must be due to extremely minute amor- 

 phous mineral matter, since the supernatant Avater in the settling-glass 

 remains cloudy and tinged with green after standing for an hour, and 

 is not cleared or decolorized by uitro-hydrochloric acid. ]So g-lauco- 

 iiitic casts of foramiuifera have been noted in these specimens. Green 

 mini is recorded at several stations in Oingala Bay. coast of Luzon, 

 and at till stations but one from ]So. li!17 to the anchorage near 

 Yokohama, a distance of about 70 miles. 



