380 DALE— CAMBRIAN MANGANESE DEPOSITS OF [April 25, 



lite ooze " similar to that described by Philippi from off the Congo 

 mouths — G. van Ingen]. These bodies contain aggregations of car- 

 bonate material, probably calcite, which have no definite orientation. 

 The section abounds with pteropod shell fragments, partially re- 

 placed with calcite. Calcite and carbonate material comprise the 

 greater portion of the section but quartz occurs as infrequent local 

 segregations and as irregular grains. Pyrite and hematite, as well as 

 a few pink and brown stained areas which are possibly secondary 

 products of manganese and iron, are sparingly present. No analysis 

 was made of this rock but with the sodium carbonate and potassium 

 nitrate bead test a manganese reaction was obtained. This bed is a 

 bluish argillaceous manganiferous limestone. 



219 B 3, overlying the limestone, is a brownish weathering olive 

 green shale. 



219 B 4 is a bed of red shale, the upper surface of which seems to 

 be limey. The upper 2 inches of this bed has a wavy structure and is 

 somewhat greenish in color. Microscopically the bed is found to be 

 a hematitic shale with occasional grains of quartz and thin rect- 

 angular laths of feldspar. Magnetite and pyrite are found as irregu- 

 lar grains in sparing amounts. 



219 B 5. With a sharp contact, the red shale is overlain by a 1.5 

 foot thick bed of nodular and pebbly reddish blue limestone. Be- 

 cause of marked lithological differences this bed has been divided 

 into four smaller subdivisions which are lettered a, b, c, and d. 

 Subdivision a consists of about 2 inches of green shale which is 

 slightly calcareous. Subdivision b is a compact pinkish limestone 

 containing pinkish or reddish mineral disseminations and occasional 

 fragments of hyolithid and brachiopod shells. Microscopically this 

 limestone is somewhat granular and crystalline, with calcite as th|e 

 dominant anisotropic mineral. Quartz occurs occasionally. Hema- 

 tite as an impalpable dust or pigment is abundant, bordering hyo- 

 lithid fragments or as irregular accumulations. A fragment of 

 probably organic substance with a cellular structure is a conspicuous 

 feature of the slide. Sponge spicules replaced by calcite are 

 noticeable. 



Subdivision c differs not very much from the two members de- 

 scribed but is nodular or pebbly and much more fossiliferous. Micro- 



