326 



STRATIGRAPHICAL GEOLOGY. 



and the upper a few slates. We have several sections crossing this area, 

 on which one can see many other rocks besides the Helderberg deline- 

 ated, and described here for convenience. The first (Fig. 36) is near the 

 north-east extremity, extending from Palmer to Burnham hill, nearly a 

 I mile and three fourths. Palmer hill is composed of 

 Lyman schist, dipping '/^° N. 48° W. In passing to 

 I the depression, which is in reality a water-shed for 

 I streams flowing northerly and southerly, — Cow and 

 I Parker brooks, — the strata, first, are vertical, then 

 I they dip north-westerly; and, finally, several meas- 

 ^ urements in a distance of thirty rods gave 80° S. 54° 

 i E, S. 30° E., and 85° S. 45° E. The rock here, near 

 y C. Closson's house, is an indurated slate, chiefly sili- 

 ■^ ceous. Next we pass up a hill over the Lisbon schist, 

 t .• perhaps dipping 80° S. 25° E. On top of the hill 

 0^1, there are good exposures of the Lyman argillitic 

 I 2 quartzites, dipping 80° S. 37° E. Immediately to 

 ^ I the east succeeds a siliceous rock, which, from dif- 

 ferent observers, has received the names of sand- 

 stone and buhrstone. It dips sometimes north-west, 

 but perhaps oftener to the south-east. On the north 

 slope of the hill the sandstone varies in position from 

 about 80° S. 18° E. to S. 2° E. This rock can be 

 followed a mile north-easterly across the road going 

 eastward to Mann's hill, or nearly to W. I. Heyer's, 

 and then is supposed to turn and follow up the hill 

 to the south-east of Burnham's house, and to con- 

 tinue south-west to Parker river. It has its maximum 

 development on the east side of the basin, and prob- 

 ably connects with the buhrstone of Fig. 38. 



Overlying the sandstone, as I suppose, is the fos- 

 siliferous limestone. It has been excavated at several 

 places quite extensively, and burnt in a contiguous 

 kiln. It is usually of a light-drab color, somewhat 

 brecciatcd; and the fossils are not conspicuous, but upon search they 

 prove to be considerably abundant. The thickness varies from ten to 



2 -t 



