446 WARREN AXD POWERS DIAMOND HILL-CUMBERLAND DISTRICT 



of fossiliferous Lower Cambrian rocks on the Joes Rock granite hill 

 south of AYest AVrentham, a short distance north of the State line. 



•'After following the southern margin of the granite hill eastward along the 

 base of the hill for a distance of several hundred feet, a change in direction 

 of the border toward the northeast takes place. Here a number of red lime- 

 stone boulders are found on the hillside. Toward the brow of the hill there 

 is a fair exposure of red shales dipping at a high angle westward and striking 

 east of north. West of these, quartzitic hed^ probably occur, as is sho\\Ti by 

 fragments in the soil and on the hillside. 



"The loose boulders on the hillside evidently are almost in situ and contain 

 Hijolithes princeps ? and H yolithellus micans ?. From the top of this part of 

 the hill it is a distance of about 100 feet to the border of the granite mass 

 forming the main body of the hill. Along the brow of the hill westward the 

 granite is purplish or brownish rock, which may possibly be fragments of 

 Olenellus Cambrian shale hardened by metamorphism." ^^ 



T^he purplish rock referred to last was found on the hill, included in 

 Joes Eock granite, as described. The inclusion is about 3 feet long, but 

 only a few inches wide. Under the miscroscope the rock is seen to be 

 quite different from the pre-Cambrian and Carboniferous schists. It 

 consists largeh' of hematite and magnetite with some quartz and musco- 

 vite. AVith the purple slate was found one of light yellowish color. The 

 fossiliferous limestone boulders were not found. 



Pennsylyaxian Eocks 



suBDivisioys 



The Carboniferous rocks of the area considered in this paper are 

 divided into two series, now separated by about 4 miles of other rocks. 

 In the eastern and southeastern part of the area the sediments of the 

 N"arragansett Basin occur. For convenience they will be called the 

 Narragansett series. In the northwestern part of the area there is an- 

 other sedimentary series which is more fully exposed near the town of 

 Bellingham ; it will therefore be called the Bellingham series. The rela- 

 tion of these two series is at present unknown, but it is probable that they 

 were formerly connected with each other and with the Carboniferous 

 sediments of the Boston Basin, the Norfolk Basin, and the newly discov- 

 ered South Franiingham Basin. The most apparent difference between 

 the Xarragansett series and the Bellingham series is in the color of the 

 sediments — the former are red and the latter are dark green. Tliere is 

 also a great difference in the amount <>f metamorphism to which these 

 sediments have been subjected. The Bellingham series has been intensely 



"Monograph U. S. Oeol. Survey No. 38. p. ."iOH. 



