300 STRATIGRAPHICAL GEOLOGY. 



of long, flattened elliptical pebbles of sandstone, having the shape very 

 nearly of whetstones used for sharpening scythes. The original rock has 

 essentially the same mineral character with the derived strata. Usually 

 the process of metamorphism, or rock-development, has been carried on 

 so far that the grains and coarser pebbles have disappeared, being merged 

 into the homogeneous argillitic mica schist. In a multitude of cases a 

 practised eye will recognize the outlines of the pebbles in these ledges, 

 which a stranger would not readily discover. No. 335 is an example of 

 another variety of conglomerate, with small rounded pebbles of quartz 

 and longer patches of a white, soft rock, the whole abundantly cemented 

 by an argillaceous paste. This variety is not common. Whether any of 

 these conglomerates may be the equivalent of the auriferous variety soon 

 to be described, becomes a perplexing question after passing the known 

 bounds of the latter. 



The Lyman group may be distinctly followed beyond the limits of the 

 special map through Lyman into Littleton. Much of it is covered by 

 later formations. The eastern border passes uninterruptedly to Young's 

 pond. The dip is at first about 80° north-westerly, but on the south side 

 of the pond it is 75° S. 30° E. Figs. 31 and 32 may illustrate the course 

 of the Lyman group in this region. The two gold mines represented in 

 Fig. 3 1 are on opposite sides of a synclinal. At Young's pond the strata 

 are monoclinal, most likely comprising only the western part of the for- 

 mation, the eastern being covered unconformably by the clay slate, in 

 agreement with the condition of things described upon page 283. Facts 

 about the Lyman group, on Fig. 31, have been presented upon pages 288 

 and 289. 



On taking the road to Young's pond from the Reduction Company's 

 mine, we first pass over supposed Helderberg slates. Turning on the 

 first road to the left, near J. E. Barber's, we find first at his house a ledge 

 of green schists. Behind the house the rock is the well known "scythe- 

 stone conglomerate" of the Lyman group, dipping south-east. This con- 

 tinues to 400 feet beyond H. Knapp's, where we find the normal argillitic 

 mica schist standing upon edge. The Lisbon group makes its appear- 

 ance by J. M. Smith's, on the turn to Young's pond, having the dip 85° 

 N. 42° W. At A. Knapp's, half way to the pond, the argillitic mica 

 schist dips S. 42° E. Between here and the pond there is a large de- 



