W. A. Tarr — Cone-in-Cone. 



203 



and in some thin lenses of cone-in-cone in Boone Co., 

 Missouri. The fibers composing the cone-in-cone layers 

 are parallel or inclined. If the latter, they are parallel 

 to the surface of the cones. 



Fig. 8. 



Fig. 8. — Section of clay rings showing relationship to fibers of calcite. 

 A — natural size. B — enlarged three times. 



The composition of cone-in-cone is significant. -Anal- 

 yses show from 60 to 98 per cent CaC0 3 , with the 

 remainder usually clay and other insoluble materials. 

 The common occurrence of cone-in-cone in shales and 



Fig. 9. 



Fig. 9. — Cone showing flaring of base. 



always in association with calcareous portions of the 

 shales would account for the presence of the clay. Prob- 

 ably the association of cone-in-cone with calcareous con- 

 cretions has a bearing on their occurrence. The writer 

 has found them in thin lenses of fibrous calcite in the 

 Pennsylvania!! shales in Boone Co., Missouri. 



