2170 



1570 — 



1225 — 



850 



655 



505 — 



355 — 



205 



100 



200 300 



Temperature -°C 



400 



— 



Distance 

 along bed - 

 Feet 



Figure 10-11. Glow curves of Niagrara limestone — lateral sec- 

 tion of quarry. 



