558 STUDIES FOR STUDENTS 



EXPLANATION OF PLATE VIII 



Fig. i. — Section 4719 (X 12). Lake Superior brown sandstone 

 from the Chequamegon Area. This section is composed mainly of 

 quartz and the accompanying figure shows the size, shape and arrange- 

 ment of the grains. It will be observed that they do not interlock. 



Fig. 2. — Section 4714 (X 12). Lake Superior brown sandstone 

 from the Chequamegon Area. The grains are somewhat better 

 rounded in this, than in the preceding section. One will quickly 

 notice the secondary quartz which in many places cements the individ- 

 ual grains together. Occasional grains of feldspar occur among those 

 of quartz. 



