I '^2 



THK MUSEUM. 



a fragment of clay slate, for it is one 

 of the plainest and least attractive of 

 all minerals. Y^t a careful study of 

 it in situ is very interesting, at least 

 to me, and develops many problems 

 not easily answered. 



In this state clay slate occurs in long, 

 narrow strips, the principal one of 

 which is in the central part of the state, 

 extending northerly in a serpentine 

 course, from the town of Royalton far 

 into Canada. In some places it is but 

 a mile in width and in others it has a 

 breadth of nearly si.x miles. It is this 

 strip that will be studied in the pres- 

 ent paper, not because it is the most 

 interesting, for such ma\' not be the 

 case, but because I chance to live not 

 far from the center of the strip and, 

 in consequence have had vastly better 

 opportunities for original study. 



Clay slate, as it is found in this 

 strip, IS interstratihed with beds of an 

 impure limestone of a bluish, or gray- 

 ish tint, and, also by beds of rnilky or 

 hyaline quartz, and, in places of beds 

 of granite. Other kinds of rock are 

 found but they are of small extent. 

 It is coarsely laminated, and is divid- 

 ed, by joints which cross each other at 

 different angles, into rhomboided 

 blocks varying in size from two or 

 three inches, to several feet in extent. 

 It is composed of very fine clay with 

 just enough organic matter to give it 

 a dirty black color, but so thoroughly 

 have the organic been decomposed 

 that no fossils have ever been found in 

 this strip. It was deposited as silt, 

 in horizontal strata, and afterwards 

 tilted at various angles. In some 

 places the strata are nearly horizontal 

 and in others they are nearly perpen- 

 dicular, but always the dip is towards 

 the east. Another peculiarity of this 



formation is that, starting from any 

 point upon the surface, the elevation 

 of the rock gradually increases towards 

 the south in the form of an inclined 

 plane, and then suddenly drops by a 

 perpendicular descent. It then be- 

 gins to ascend only to drop again. 

 Take a flight ot stairs having very broad 

 and comparatively low steps, and lay 

 it flat upon its back and you will have 

 a very good representation of this pe- 

 culiarity. Again it will be noticed 

 that the entire surface of this strip con- 

 sists of a succession of hills and valleys 

 all extending in a northerly and south- 

 erly direction, following the general 

 trend of the strata. Yet very few of 

 the streams follow the course of these 

 valleys. With very few exceptions 

 they follow deeper, and transverse val- 

 leys across the strata 



This much may be seen by a casual 

 glance at the surface of the country. 

 Now for a little theory. For several 

 years I have been studying this forma- 

 tion very carefully and have just about 

 learned enough so that I can begin to 

 work intelligently. I intend to devote 

 considerable time to field work as soon 

 as the weather will permit and I be- 

 lieve, that, before the end of another 

 year, I shall have made some interest- 

 ing deductions. 



From what I have already learned, 

 I believe, as 1 have stated, that the 

 clay slate was deposited as silt upon 

 the bed of an immense body ot water, 

 possibly the ocean itself, and that by 

 some internal force coming from the 

 east the entire mass was tilted to its 

 present position. This operation evi- 

 dently produced the joints, and, not 

 only this, but, by allowing the layers 

 to slide freely from their positions, 

 produced the hills and valleys as well. 



