353 ^ 



October 3, 1860. 



Dr. C. T. Jackson, Vice-President, in the Chair. 



Prof. Edward Hitchcock, of Amherst, made a commu- 

 nication on the conglomerate of Vermont, which contains 

 elongated, flattened, and curved pebbles of quartzose 

 nature, and sometimes of pure hyaline quartz ; this sub- 

 ject had been formerly presented to the Society by his 

 son (see meeting of Jan. 4, 1860.) 



His observations had been made at Newport, wliere these dis- 

 torted pebbles were first noticed, and at Wallingford and Plym- 

 outh, Vt., in the Green Mountains. He exhibited diagrams, 

 showing the size, shape, and relation of these pebbles to the con- 

 glomerate enclosing them, and the gradual passage of the rounded 

 and water-worn masses into the folia of the schists. At Newport 

 the greatest elongation is in the direction of the strike, but in Ver- 

 mont in the direction of the dip ; in Plymouth he had found the 

 pebbles of one surface continuous with the schistose lamince of 

 another. In some localities this quartzose conglomerate is inti- 

 mately associated with gneiss, and seemingly a variety of it ; he 

 had no direct proof of this, but believed that there is a continuous 

 series of changes from these quartzose elongated pebbles, through 

 the talcose and micaceous schists, to the gneiss, — that all are 

 varieties of the same rock. The gneiss of the Green Mountains 

 has these conglomerates and schists on the east and west sides, 

 the former being the uppermost. He drew a section of the moun- 

 tains from Wallingford to Plymouth, embracing an extent of sur- 

 face of about eleven miles, where these rocks occupy similar posi- 

 tions on each flank ; according to appearances here presented, the 

 dip of the strata indicates an immense amount of denudation. 



He adhered to the opinion that these pebbles have been bent 

 since their deposition, and while they were in a plastic state ; they 

 are not only elongated, but indented and curved around each other 

 in some localities ; the simple curvature of the strata might explain 

 the elongation in the line of strike, but not the other phenomena 

 presented. Some of these pebbles in Vermont are pure quartz. 



PROCEEDINGS B. S. N. H. VOL. VII. 23 NOVEMBER, 1860. 



