488 FERTILIZERS. 



the surface. Nature, in general, brings out the fertilizing lime, and the rains spread it 

 over the surface just about fast enough, perhaps. Yet it has occurred to us whether by 

 some simple process it could not be made to give it up more rapidly. Suppose, for in- 

 stance, that upon one of those black looking points of rock that show themselves often in 

 cleared fields within the limits of this formation, a quantity of ashes were spread. Might 

 not some of the carbonic acid of the limestone unite with the potash, and thus prepare 

 two good fertilizers, viz., hydrate of lime and carbonate of potash ? We have never made 

 this experiment, and it may not succeed ; but we suggest it as one easily tried by any 

 farmer who finds himself located anywhere along that broad deposit which on our map is 

 called calciferous mica schist. And the same experiment might work well over that other 

 wide strip marked as talcose schist ; for we have found that much of this rock contains 

 carbonate of lime. Without such an experiment, however, we have already intimated 

 how rich a boon to Vermont is this fact ! Of more value, probably, than her marble, 

 slate, granite, and soapstone, especially when we add that nearly all the valleys and mod- 

 erate slopes west of the Green Mountains are still more abundantly supplied with this 

 fertilizing agent. We are certain that no other New England State will compare at all 

 in this respect with Vermont. 



To return to the subject with which we started, viz., the metamorphism of this rock, we 

 are of opinion that it was originally a limestone formation charged with a good deal of 

 silex, and perhaps with silicates and organic matters. In the process of metamorphism 

 the carbonated or alkaline water with which the rock has been charged has dissolved and 

 abstracted a good deal of the carbonate of lime and formed silicated minerals, such as 

 mica and feldspar, which have more or less, and sometimes entirely, changed the rock 

 into mica schist and gneiss. For no one can look at the range of gneiss extending south- 

 erly from Ascutney, on our map, without being satisfied that in some way or other the 

 calciferous mica schist south of the region of Ascutney has been mostly changed into 

 syenite, quartz and gneiss. If the schist did not reappear as we go southerly, we might 

 hesitate to say that the gneiss and syenite were forms of its metamorphism ; or if the 

 western side of the gneiss did not essentially agree with what would be the western side 

 of the schist were it continuous, we might hesitate. But as it is, and with the evidences 

 of metamorphism which other parts of the State present, we see no way to escape from 

 the conclusion. At any rate, as we go southerly, as a general fact, the calcareous element 

 diminishes and the schistose element increases. Can it be that the narrowing of the 

 formation as we go south, and especially in Massachusetts and Connecticut, should be 

 the result of the abstraction of the lime, so that the lateral pressure was able to bring the 

 residue into a narrower compass ! 



Perhaps this formation affords the finest examples of changes in a rock on the line of 

 strike which we shall be able to present, though we have some other very good ones. 

 But we have always been jealous of supposing changes on the line of strike, because every 

 geologist knows how difficult it is to follow a rock with certainty on the line of strike in 

 such a region as New England. Where we must cross deep valleys covered with drift, 

 when we reach the opposite hill we are not certain but its strata may be so folded around 

 those we have been tracing as to be parallel to them, and not their prolongation. But the 

 great extent of this formation, not less than 300 or 400 miles, and the great and decided 

 changes which occur, make our conclusions on this subject quite safe. 



