INDUSTRIAL GEOLOGY. 145 



-which this power has been exerted. Of course wave power cannot be exerted 

 very deep down — indeed ouly for a few feet, and so you may well ask now it is 

 that waves of the sea can pile up rocks miles in tliickuess. This is possible only 

 as the same rocks sink as they rise. All our coasts are unstable to-day. The 

 coasts of Europe skirting the Baltic sea are rising, while those of Greenland 

 and the North American continent from Labrador to New Jersey are as surely 

 being depressed. Just such a slow subsidence has made it possible, all through 

 the world's progress, for the ocean to pile up new made rock beds even for 

 miles in thickness. If we examine the floor of the ocean to-day we find this 

 process of rock building in active progress. We also find that if the water is 

 shallow, as is usually the case with the beach at favorite seaside resorts, then 

 the waves are heavy imd thunder against the shore, with resistless force at all 

 times of storms and heavy seas. The waves in such cases will bear along coarse 

 particles, and so in such cases the rock will always be coarse or sand-rock, and 

 often conglomerate. Where the water is deep the force of the waves will be 

 broken, their force lessened, and so only finest rock can be borne by the waves, 

 and so clay rock will be the result. Sea animals, those that form shells, or 

 secrete lime skeletons, like the coral animals, can only thrive in clear, clean 

 water, and so they will slowly build up lime rocks, only where the water is so 

 deep that the force of the waves is not felt, and so no earth particles leave 

 their stain to vex or hinder the sea life in the important work which is given 

 into its hands. Thus we ever find sand formation in shallow water, clay 

 where the water is deeper, and lime where the water is so deep that the sea life 

 is undisturbed by the tilth of eroded rock. We know then as we see any rock 

 much of the conditions that looked upon its birth and development. We know 

 that such huge sand-stone cliffs as are seen in the Pictured rocks of Lake 

 Superior were builded on a shallow shore, that the shales which overlie them 

 to the south were as surely thrown down as fine sediment in a deeper sea, while 

 the huge lime masses so often seen in our northern Michigan outcrops were the 

 result of ages of life of sea aiiinials which could thrive only and build up their 

 vast rock beds in a comparatively deep ocean. 



We now know that there has been not only gradual progress or development 

 in world building, but in life building as well. At the dawn of the life era were no 

 plants, only the sea weeds, and no animals except the lower forms of sea animals, 

 and as we find to-day, the general style of life was the same in all parts of the 

 world, in fact even more so than now, for as we have already seen tlie conditions 

 of the world were then more uniform. There was then no polar ice and chill to 

 freeze and drive out most life forms, wherever they could force their deadly 

 presence. Again, later, we find a higher type of life, though many of the lower 

 forms or related forms still hold on. Later, land plants, fishes and other higher 

 forms gave added attractiveness to the then world, as their remains in the 

 rocks which have come to us as the result of the world building of that time 

 positively affirm. Later, huge reptiles — sea, land, and flying reptiles — made the 

 earth a scene of savage ferocity. Soon all our vegetable forms as witnessed 

 to-day, our modern fishes, and the lowest birds and mammals come as the 

 result of that gradual unfolding of life, which under God's laws has ever been 

 going on since the dawn of the creation of life, away back in the indefinite 

 past. Later came our modern birds, and all orders of mammals, some of 

 which were tremendous in size. As we look upon the remains of these huge 

 beasts, much larger and more numerous than to-day, we can well rejoice that 

 in the plans of a loving Father the time of man was not yet. 



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