ARCILEAN FORMATIONS. 



255 



N". line of K. E. qr. of S. W. qr., Sec. 35, Portland), a rock of similar 

 nature, but of light buff color, was penetrated to a depth of 18 feet, 

 below 36 feet of drift, when quartzite was reached. In the S. E. qr. 

 of Sec. 3, town of Waterloo, after 18 feet of drift, 41 feet of what 

 was described as a rather soft, sandy red rock, was penetrated, below 

 which a hard rock, probably quartzite, was found. The accompany- 

 ing cut shows the relations of this rock with the quartzite and con- 

 glomerate. 



FIG. 22. 





NORTH AND SOUTH SECTION THROUGH PORTLAND QUABTZITE. 

 1. Quartzite. 2. Conglomerate. 3. Shaly Sandrock. 



Figure 23 shows the horizon which the quartzite and the accompa- 

 nying formations occupy. The nearest approach of the Trenton and 

 St. Peters, in their normal character, is about two miles. 



FIG. 23. 



PROFILE SECTION, SHOWING THE RELATIONS OF THE PORTLAND QUAHTZITK. 

 1. Quartzite. 2. Shaly Sandrock. 3. Lower Magnesian Limestone. 4. St. Peters Sandstone. 5. 



Trenton Limestone. 



"Without assuming demonstration, it seems most in harmony with 

 all the facts, and freest from gratuitous assumptions to refer the 

 conglomerates, sandstones and shaly sandrock to the period of the 

 St. Peters, and they will be found so mapped. 1 It is to be remarked 

 (1) That these quartzites were originally sandstones and conglomer- 

 ates. (2) That they were metamorphosed before the deposit of the 

 neighboring horizontal rocks, since the pebbles included in the latter 

 are metamorphic. (3) That they were tilted before the deposit of 

 horizontal rocks, as shown by their unconformability. (4) That their 

 upheaval and metamorphism were probably synchronous and congen- 

 ite. (5) That extensive erosion took place before they were com- 

 pletely covered and protected, as shown by the fact that they expose 



4 On the accompanying map the area of quartzite in Sec. 34 is placed one-third mile 

 too far north. 



