THE PENNSYLVANIAN PERIOD 659 



sented widely by a little foraminiferal shell (Fusulina secalicus, 

 b, Fig. 456), which, had about the size and form of a grain of wheat. 

 Their abundance gives character to the Fusulina limestone which 

 occurs in America, Europe, and Asia. Corals were rare, as might 

 be expected under the environmental conditions of the time. 



Map work. No reference to map work has been made since that at the 

 close of the chapter on the Ordovician, p. 535. Experience has shown that 

 if the principles of stratigraphy as illustrated by the Cambrian system, are 

 well developed as suggested on p. 506, further map work may be deferred to 

 about this point. Many of the maps available for this work involve most of 

 the Paleozoic systems of rock, and if map work on these systems is taken up at 

 this point, it may be made to serve as a review of the history of the periods 

 when these systems were deposited. 



The following folios of the U. S. Geological Survey are among those espe- 

 cially serviceable in this connection: Arizona, Clifton, Globe; Arkansas-Mis- 

 souri, Fayetteville; Arkansas-Oklahoma, Winslow; California, Coif ax, Nevada 

 City Special, Redding; Colorado, Needle Mountains, Walsenburg; Illinois- 

 Indiana, Danville; Indiana- Illinois, Patoka; Kansas, Independence; Massa- 

 chusetts, Holyoke; Missouri, Joplin; Montana, Livingston; New Jersey, 

 Franklin Furnace; New York, New York City; Oklahoma, Atoka, Tishomingo; 

 Pennsylvania, Ebensburg, Elkland-Tioga; Tennessee, Briceville, Kingston, 

 Standingstone; Tennessee-Georgia, Ringgold; Utah, Tintic; Virginia-Tennessee, 

 Bristol; Virginia-West Virginia, Monterey; Washington, Snoqualmie; West 

 Virginia, Charleston; Wisconsin, Lancaster-Mineral Point; Wyoming, Alla- 

 din, Cloud Peak-Fort McKinney, Sundance. 



If a fuller list is desired, the following may be added: Arizona, Bisbee; 

 Colorado, Ouray, Rico; Illinois, Chicago; Maine, Penobscot Bay, Rockland; 

 New Jersey, Passaic; Oklahoma, Muscogee, Talequah; Tennessee, Chattanooga; 

 Wisconsin, Milwaukee; Wyoming, Absaroka (Crandall Sheet), Bald Mountain- 

 Dayton, Yellowstone. If the full set of folios is available, folios even more 

 suitable for special localities may be selected. 





