62 THE CANADIAN NATURALIST. [Vol. VUK 



Thus we pee that the gigantic forces at work, building up find 

 carving out a monument of a long age, were not equally potent. 

 The surfaces of ihe beds of sandstone in many places were 

 sculptured before the succeeding deposits of igneous matter. 



The relative position of the melaphyres and amygdaloids is 

 nearly constant; the former compact rocks being at the base, 

 pass gradually through the various stages till the upper beds be- 

 come perfectly amygdaloidal. The different b< ds vary in thick- 

 ness from a few 1e<t to more than 150 feet, and have the lines of 

 demarcation between them often quite distinct. The change from 

 the compact tr; ps to the amygdaloids is probably due to the 

 Structure of the deposits rather th; n to the greater and more re- 

 cent internal ch; .ng( s. or metamorphoses, as the upper beds of 

 the original liappean ove ifl< ws would incline to a more vesicular 

 stiucture than those subjected to a heavier pressure at a greater 

 depth. 



Along the lower waters of the Eagle River, a section of the 

 Cupriferous series is exposed for a distance of more than two 

 miles across the formation. It was measured by the Michigan 

 Geological Suivey, and more than 160 beds were plotted. This 

 together wiih tie section of Portage Lake region may be sum- 

 med up as ft hows, in descending order, having a vertical thick- 

 nefs of: 



Conglomerates and sandstones dipping ~\ 

 under the lake, but of which there is an ex Y 2,500 feet, 

 posure of, ) 



45 bids of melaphyres, amygdaloid*, con-^\ 

 Itinerates, and sandstones — there being 10 j 

 eds of the sedimentary rocks with an aggre- j- 1,500 " 

 gat. thickness of 400 feet, reaching to the j 

 "Ash Bed," J 



45 beds of melaphyres. and amygdaloids ) -. .^ u 

 with some thin seams of sandstone, j ' 



18 beds of d writes, beneath which is the re- | ^ 9 ™ u 

 preset) tative of the Allouez Conglomerate, J 



60 beds of melaphyres and amygdaloids reach- 

 ing to the (recently discovered) supposed re- J 1,200 

 presentative of the Calumet Conglomerate, 



Melaphyres. amygdaloids and a number of 



c 



beds of conglomerates and sandstone, extend- ; ~ ~™ 

 ing from the Calumet Conglomerate, to the j 

 base cf the series, J 



Total thickness of the Copper-Bearing Series ) , * r^q *. . . 

 on Keweenaw Point as far as known, J ' 



