TITLES AND ABSTRACTS OP PAPERS 75 



GEOLOGY OF THE CUMBERLAND-DIAMOND HILL DISTRICT, MASSACHUSETTS- 

 RHODE ISLAND 



BY CHARLES H. WAREEN AND SIDNEY POWERS 



(Abstract) 



The Cumberland Diamond Hill district is well known from the occurrence 

 of cumberlandite on Iron Mine Hill. The other most striking geological fea- 

 tures are a stock of riebeckite-aegirite granite and a large mass of vein quartz 

 forming Diamond Hill. The alkaline granite is closely allied to the Quincy- 

 Blue Hills riebeckite granite and to a small stock near Sharon, south of the 

 Blue Hills. 



Evidences of four periods of igneous activity are found in the region. The 

 earliest is pre-Cambrian, but later than the deposition of the green schists and 

 quartzites in the Blackstone River Valley. Gabbro, cumberlandite, and labra- 

 dorite porphyry dikes were intruded. The second period is Lower Paleozoic. 

 All the biotite granites of this region are thus dated from the evidence found 

 near North Attleboro, where the granite is thought to cut Cambrian sediments. 

 The third period is Devonian (?), at which time the alkaline granites were 

 intruded. These granites cut the biotite granites, and pebbles of them are 

 found in the Norfolk Basin sediments of Pottsville age. The last period is 

 Pennsylvanian, when dacitic lavas were extruded at Diamond Hill. At the 

 close of the Carboniferous the dacites were faulted and brecciated. Up the 

 fissures so formed came hot siliceous waters, replacing the dacite and forming 

 the mass of quartz at Diamond Hill. 



Presented by Mr. Powers in abstract without notes. 



SEDIMENTARY CHARACTER OF GARNETIFEROUS HORNBLENDE SCHIST, 

 HANOVER, NEW HAMPSHIRE 



BY JOHN WESLEY MERBITT 2* 



{Abstract) 



A garnetiferous hornblende schist found at Hanover, Grafton County, New 

 Hampshire, has been described in Bulletin 150, United States Geological Sur- 

 vey, and tentatively classed among schists and gneisses of igneous origin. 

 Field and petographic study of this rock and its associates furnish many 

 evidences of sedimentary origin. 



Eead in full from manuscript. 



OOLITES OF THE CHIMNEYHILL FORMATION, OKLAHOMA 

 BY CHESTER A. REEDS ^^ 



{ Abstract) 



The oolites of the Chimneyhill formation are for the most part calcareous. 

 In the upper portion of the bed, however, bands, stringers, and lentils of chert 



24 Introduced by J. W. Goldthwait. 



25 Introduced by E. O. Hovey. 



