184 ANNUAL REPORT OF THE Off. Doc. 



and clay, and with organic substances, the remains of marine organ- 

 isms. In subsequent geological disturbances these beds were up- 

 lifted from the waters, sands forming sandstones, the clays, shales; 

 the ocean ooze, the limestones, and these in turn were again 

 attacked by the same pulverizing, transporting and dissolving agen- 

 cies. These rocks, however, exhibited some contrast to the original 

 crystalline rocks, in that the sandstones and shales contained less, 

 the limestones a larger proportion of soluble materials than their 

 parent rocks. 



Other differences, too, marked these later periods. During the 

 changes in position of the earth's strata streams of molten rock 

 broke through rifts in the surface, forming the great crystalline 

 trap dykes found in Adams, Leb,anon and more eastern couuties. 

 Also, as the result of heating, compression and other agencies, sedi- 

 mentary rocks became crystalline, as we see them in the meta- 

 morphic granites, porphyries and schists of the southeastern coun- 

 ties. Moreover, the great ice streams of the north overflowed 

 the northern counties, chiseled the mountain sides, and deposited 

 great masses of well-mixed boulders and flne debris, thus forming 

 the glacial drift. 



Biological agencies, too, have contributed largely to soil forma- 

 tion. A great variety of organisms from the minute bacterium, to 

 the giant of the forest, have, each in its own way, and in its own 

 order, helped to transform rocks into the soils we till. Helping 

 to dissolve the minerals, gathering up with their organs the ele- 

 ments they required, and upon their death leaving these elements as 

 a more concentrated, better elaborated food for the succeeding ten- 

 ants, the earlier inhabitants have, in their last decay, continued 

 to dissolve the earthy vvalls about them. Let it be remembered that 

 these soil-forming agencies are still at work, that the soil w^e till 

 are not the product of a single geological transformation, but have 

 been made over and over again, and that even now our fertile 

 plains are paying excessive tribute to the sens, wliile the roeks 

 beneath our subsoil and the mountain top.s are erumbliug and turn- 

 ing over annually to our use the rich material from which we shall, 

 if we are wise, coin golden harvests. 



Whenever we bring the subsoil to the air by drainage, or by aid 

 of our plowshares, we set up oxidizing processes, change the soil 

 climate, and fit it for a new flora; conversely, when we suffer our 

 surface lands to become too compact, or to be shut off from the 

 air by standing water, we set up a train of reducing actions, by which 

 wholesome foods are turned to poisons, and make the former soil 

 residents yield place to others that minister less to our wants. 



As masters of the land we are not, however, interested in geology 

 as a history of the past, but study its processes and forces that we 

 may make them servants to our present use, as the master of the 

 sea studies the ocean chart, so that by setting the sails and turning 

 the rudder of his frail bark he may make the winds and currents 

 his servants, to carry him whither he wills. 



The soil serves the plant in a variety of ways. Its texture, its 

 heat and cold, moisture and drought, helpful or harmful population 

 of lower organisms, all form factors of environment important in 

 determining its fitness for the satisfactory development of our crops. 

 No system of soil study, classification or judging is complete \JQle88 

 it give due attentiO!} to epich of these factors. 



