160 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



increases and the cleavage surfaces are mottled by large aggregations of 

 the green mineral. The thickness of the plates is made up of highly crys- 

 talline quartz, at times fused into a complete vein quartz and carrying 

 garnets and pyrites, often in large quantities. It is frequently also Avholly 

 barren over broad areas. 



To the east of the great serpentine bed in the north of Chester the rock 

 is gnarled and contorted in a most marvelous manner; the quartz laminae 

 bi-anch out and grow thin in rapid alternations, and many small quartz veins 

 run in all directions. This holds for a half mile eastward, until, on the first 

 road running north, the corrugation lessens suddenly and disappears, and 

 the schist takes the normal form described above. 



Several beds of amphibolite, 7 to 12 feet thick, are interposed in the 

 schist, and the transition from one to the other is in all cases very sudden. 



The succession of the beds next above is well shown in the second 

 cutting north of Chester station, and the section is given in detail to show 

 the rapid and repeated alternations of micaceous and hornblendic strata. 

 The section runs from below upward: 



Section north of Chester station. 



Feet. 



Sericite-schist 3 



Amphibolite 1 



Sericite-schist IJ 



Amphibolite 2 



Sericite-schist 1 



Amphibolite 2 



Amphibolite . . 6 



Sericite-schist 8 



Amphibolite 10 



Sericite-schist 6 



Amphibolite 6 



Sericite-schist 12 



Sericite-schist ' 3^ Amphibolite 4 



Amphibolite \ j Sericite-schist 6 



Sericite-schist 3 ' 



A very short distance separates this section from the cutting nearest 

 the station, representing the strata next above those just described. This 

 cutting exposes 217 feet, and in this distance are 23 beds, from 1 to 20 feet 

 in thickness, of alternating sericite and amphibolite. (See PI. VI, fig. 4, 

 p. 306.) Many of the sericite-schist layers contain in abundance large, dis- 

 tant garnets in every stage of change to chlorite. 



Following the line eastward from the station to the junction witli the 

 Conway mica-schist the greenish-gray sericite-schist in this upper jjortion, 



