C URRENT PRE- CAMBRIA N LITER A TURE 437 



Emerson J describes the Algonkian rocks occurring in the south- 

 western corner of the Holyoke quadrangle in Massachusetts and in the 

 area to the west. These are gneisses and limestones making up a series 

 called the Washington gneiss. They are of sedimentary origin with 

 the possible exception of the hornblende-gneiss of East "Lee. 



In general in western Massachusetts the Washington gneiss appears 

 in oval areas surrounded by younger strata, the line of these ovals 

 extending south from the Hoosac Tunnel along the crest of the Green 

 Mountain plateau. The gneiss enters the Holyoke quadrangle at the 

 southwest corner and runs up across the town of Tolland, narrowing 

 to a point near Black Pond. 



Woodworth 2 describes the Algonkian rocks in the lower portion of 

 the Blackstone Valley and west of Providence, R. I., near the western 

 margin of the Narragansett basin. From the typical development of 

 the Algonkian rocks aiong the Blackstone River between Woonsocket 

 and Pautucket, they are called the Blackstone series. This series is 

 divided into the Cumberland quartzites ; the Ashton schists, represent- 

 ing the finer sediments succeeding the deposition and partial erosion 

 of the Cumberland quartzites, and in part probably igneous in origin \ 

 and the Smithfield limestone, apparently of sedimentary origin. As yet 

 no facts have been discovered to show whether the limestones are of the 

 same age or newer than the Ashton schists. The rocks of the Blackstone 

 series are separated and penetrated by granitic intrusions or batholites- 



The Blackstone series is assigned to the Algonkian because of the 

 difference in metamorphism of the Blackstone series and Lower Cam- 

 brian strata, bearing Olenellus fauna, in North Attleboro. The Cam- 

 brian strata are little altered and lie in close proximity to the granite. 

 Four miles west the Blackstone series is infolded with a similar granite 

 and much altered. 



Kemp 3 gives a petrographical account of the granites of the 



I B. K. Emerson : Geology of Old Hampshire County, Massachusetts, compris- 

 ing Franklin, Hampshire, and Hampden Counties : Mon. U. S. Geol. Surv., No. 29, 



1898, pp. 19-30. With geological map. This covers the area of the Holyoke quad- 

 rangle and in addition a narrow area to the north and east. 



Holyoke folio, Massachusetts-Connecticut : Geol. Atlas of the U. S., No. 50, 1898. 



2 Geology of the Narragansett Basin, Part 2, by J. B. Woodworth : Mon. U. S. 

 Geol. Surv., No. 33, 1899, pp. 104-118. With geological map. 



3 Granites of Southern Rhode Island and Connecticut, with Observations on 

 Atlantic Coast Granites in General, by J. F. Kemp : Bull. Geol. Soc. Am., Vol. X r 



1899, pp. 361-382 ; with plates. 



