THE CHESTER AMPHIBOLITE AND SERPENTINES. 117 



No. 4. Normal dark-green, sUglitly oily serpontino, from the center of the large Middlcfleld bed, taken from wlicre 

 the road crosses the ChesterMiddletield line. 



No. 5. Black.green serpentine, weathering to pale nickel-green, with much chronute. I-orth ISlandford. From 



"The Crater." „ , ^. ,, . 



No e Gray, spUnterv serpentine enveloped in talc. Chester. From the east wall of the old mine. 



No. 7. Serpentine from the lower bed at Osborn-s quarry, Blandford, which stUl retains the cleavagH of sahlite and 

 in places considerable remnants of the mineral. 



No. 8. Enstatite changed to serpentine. Granville. H. Cooley's. 



No. 9. Black serpentine with bastite. Russell. 



Nolo Black serpentine containing marmolite (bastite). EusseU. Atwater's quarry. 



No. 11. Slightly altered, nearly colorless enstatite, from Downey's, in GranvUle; added for comparison. 



The constant content of nickel, cobalt, and cln-omium in all these 

 analyses where it has been searched for is very interesting and may be 

 taken as an indication of the eruptive origin of the whole series, which 

 would, however, involve the derivation of large beds of white crystalline 

 limestones, both dolomitic and quite purely calcareous, from the same 

 basal ei-uptive rocks. 



THE CHESTER EMERY BED. 

 HISTORY OF DISCOVERY AND WOBKINa OF THE BED. 



Not the least interesting element in the peculiar geology of the west- 

 ern part of Chester is the great magnetite-emery bed which lies along the 

 upper (eastern) line of junction of the hornblende-schist with the sericite- 

 schist and extends from the Westfield (better Agawam) River southward 

 nearly to the south hne of the town and nearly as far as the great horn- 

 blendic band retains its maximum thickness. 



The history of the discovery of tins bed has often been told, and 

 deserves to be retold. The credit of the discovery and its first announce- 

 ment belongs to Dr. C. T. Jackson. I remember how Professor Shepard, 

 when taking my college class through the cabinets in 1865, stopped at the 

 old State geological collection made by President Hitchcock dm-ing his 

 survey of Massachusetts, and took down the specimen of magnetite col- 

 lected from the Chester bed and pointed out to us the emery which it 

 contained, to show us how near Dr. Hitchcock had been to numbering this 

 among his many discoveries. Dr. Hitchcock had described several beds of 

 magnetite for the first time in his final report.' They were located in the 

 western part of Chester, in hornblende-schist, and none of them exceeded 



1 foot in width. 



For the next events in the history o f the locality I must have recourse 



1 GeoloRy of Massachusetts, 1844, pp. 194, 612. 



