368 



Scientific Geology. 



into the west part of Chester, where it appears on the east side of 

 Westfield river, rising to the height of 300 to 400 feet ; and is suc- 

 ceeded on the east by talcose slate, which rises still higher. I exam- 

 ined this rock in the south part of Middlefield, and found it distinctly 

 stratified ; the strata running a little east of north, and dipping east- 

 erly, from 70° to 80°; corresponding, in these respects, with the ad- 

 joining strata. On the west this bed is succeeded by distinct horn- 

 blende slate, both in Middlefield and Chester. In the latter place the 

 serpentine is stratified with a good deal of distinctness, and exhibits 

 also a slaty structure. The dip, corresponding with that of the talcose 

 slate on the east, and the hornblende slate on the west, is nearly per- 

 pendicular ; and the direction rather more east of north than in Mid- 

 dlefield. Forming the east bank of the river, the ledges of this rock 

 seem to have suffered much from abrading agents ; and the surface is 

 much broken to pieces and the sides very steep. 



I observed the Flora of this serpentine ledge to be rather peculiar. 

 It abounded with the sassafras and prunus borealis ; the former of 

 which, especially, is scattered rather sparsely over the neighboring- 

 hills. Polygala paucifolia, Saxifraga pennsylvanica, and Convallaria 

 bifolia, I noticed also in great quantities. Ilex canadensis I observed 

 likewise, as well as a rare species of Arenaria. Lichens and moss- 

 es, however, are rarely seen upon this serpentine. 



Specimens that may be called noble serpentine do occur in Middle- 

 field ; but for the most part the rock is the common variety, of a pale 

 green color, and somewhat foliated structure, abounding, however, in 

 dark spots from the presence chromate of iron. 



Following the direction of the strata southerty from Middlefield a 

 few miles into Blanford, we come to the bed of limestone, discovered 

 since the first part of my Report was finished, and which I have al- 

 ready described. Little more than a mile north of this limestone, 

 and about five miles northwest of Blanford meeting house, on the old 

 road to Becket, and on the northeast side of a pond, there exists a 

 bed of serpentine which shows itself at the surface over a space about 

 30 rods in diameter, and it rises 30 or 40 feet above the general level. 

 This large bed evidently occupies the same geological position as 

 that in Middlefield ; for the hornblende slate, frequently epidotic, lies 

 in immediate contact with it on the west side; and though no rock in 

 place appears on the other side, yet we have much reason to believe 

 that talcose slate, or talco-micaceous slate, exists there. Not improb- 

 ably this serpentine is connected without interruption with the Mid- 



