546 



APPENDIX. 



Section in West Central Massachusetts. 1 



Names of Formations. 



Chicopee shale. 



Granby tuff. 



Thickness 

 in Feet. 



200 1 



580 



Characteristics. 



Sandy carbonaceous shale. 



Agglomerate of diabase, interst ratified with 



sandstones. 



Blackrock diabase. 



Volcanic cones and dikes of diabase. 



' Longmeadow sand- 

 stone. 



1000 



Feldspathic, ferruginous sandstone. 



Sugarloaf arkose. 



4060 



Feldspathic sandstone and conglomerate (west 

 side of Triassic trough). 



5 fl 



Mount Toby con- 

 glomerate. 



Unconformity _^~> 



Bernardston series. 



I 

 Unconformity ~^~^ 

 Leyden argillite. 



1950 



300 



Basal conglomerate of slate and crystalline 

 rocks (eastern side of Triassic trough). 



Dark mica-schist, with several beds of amphi- 

 bolite, over quartzite (650 feet) containing a 

 bed of highly crystalline limestone (20 ? feet) 



Black fissile slate. 



Conway schist. 

 Amherst schist. 

 Brinfield fibrolite- 

 schist. 



Goshen schist. 



**< Unconformity -*■ 



Hawley schist. 



Savoy schist. 



Chester amphibolite. 



Rowe schist. 



Hoosic schist. 



5000? 



2000? 



2000? 



5000? 



3000? 



4000? 



1500 



The Conway schist is a fine-grained, carbona- 

 ceous, muscovite-schist, much contorted. The 

 Amherst schist is a rusty mica-gneiss, im- 

 pregnated with granite. The Conway, Am- 

 herst, and Brinfield schists are perhaps geo- 

 graphic variations of the same formation. 

 The granite was probably erupted during the 

 Carboniferous period. 



Dark, flaggy schist with interbedded gneiss. 



Green sericite-chlorite schist, with beds of am- 

 phibolite and manganese silicates. 



Chloritic, quartzose sericite-schist, with beds 

 of amphibolite, grading into feldspathic mica- 

 schist. Many intrusions of granite. 



Epidotic, hornblende-schist, with beds of mag- 

 netite and emery near top; contains beds of 

 pyroxene rock, enstatite rock, and dolomite; 

 often replaced by serpentine and steatite. 



Quartzose sericite-schist; sometimes indistin- 

 guishable from the Hoosic schist. Some 

 granite. 



Feldspathic mica-schist, with granite. 



1 Emerson, Holyoke (Mass.-Conn.) folio, U. S. Geol. Surv. In the folio, the beds here classed 

 as Triassic are called Jura-Trias, the Ordovician and Silurian are classed together under the name 

 Silurian, and the Proterozoic is called Algonkian. 



