PEESTWICH CRAG-BEDS OE SFEFOLK AND NORFOLK. 



327 



Sometimes tlie lower beds have been eroded previously to the de- 

 position of overlying beds, as in the following section at Eamsholt 

 (fig. 6). 



Fig. 6. — Section in the Bed Crag at Ramsholt. 



Eed Crag with few shells and 

 I some copi'olites, 10 feet. 



c. Beam of coprolites. 



SheUy Eed Crag, 3 feet. 





>^:— --=!». |- Probable level of Coralline Crag. 



In one instance only have I seen ripple-marks preserved in the 

 Eed Crag. This occurred in the clifi" at Bawdsey, where the argilla- 

 ceous laminae of one bed retained each a ripple-marked surface, which 

 in the section showed like the crumpled leaves of a book (fig. 7). 



Figs. 7 & 8. — Sections in Bawdsey Cliff. 

 Fig. 7. Fig. 8. 



Laminas of ochreous clay and 

 of shelly sand. 



Bedof laminated clay and sand (h) with 

 cracks at top filled with clay from a. 



Another feature noticeable at times in the same cliff shows that 

 probably the shoals of the Eed-Crag sea were occasionally left dry — 

 their surfaces fissured by the sun and air, and the cracks filled with 

 the materials of the bed afterwards thrown down upon them (fig. 8), 



Elsewhere a crag-seam has been pressed down into an under- 

 lying bed, and the upper part afterwards removed as in fig. 9. 



Fig. 9. — Section in Bawdsey Cliff. 



Ochreous clay. 



Crag in hollows on top of 

 Ded of grey clay with 

 seams of ironstone. 



Crag. 

 Ochreous clay. 



The oxide of iron, to the presence of which the Red Crag owes 

 its distinctive name, is at places so abundant as to give rise to 



2 A 2 



