Plate XXII.— HEMATITIC CHERT FROM NEGAUNEE. 



This plate represents the same phenomena as PI. XXI, but in a more satisfactory way. The folding 

 has shattered the chert layers throughout. Along all the openings between the chert fragments 

 hematite has formed or has been forced In by pressure. A later folding has slightly shattered 

 the rock, .and in the cracks minute veins of magnetite have formed. The specimen beautifully 

 illustrates the action of material when folded in the zone of combined fracture and flowage. 

 The regularity of the fracturing of the chert layers in a direction almost transverse to their 

 length is noticeable. This suggests that the cracks formed in tensile planes when the chert 

 belts were being bent. 

 350 



