LITTLE COMPTON AND NEWPOKT NECK SHALES. 383 



of quartzite lying as far north as Newfoundland and carried southward by 

 glaciers, the absence of other pre-Carboniferous rocks among the pebbles is 

 striking-. 



LITTLE COJIPTON AND NEWPORT NECK SHALES. 



The distribution and general characteristics of the shales in western 

 Little Compton and along the western shore of Newport Neck have already 

 been sufficiently described in Chapters V and VI, pages 281 and 316. 

 The shales in question are closely related lithologically, and are evidently 

 not similar to any known Carboniferous deposits of the basin. The charac- 

 teristic feature is evidently the presence of thin layers of dolomitic limestone 

 in both areas, and the presence at various points along southern Newport 

 Harbor of quite thick beds of a white limestone, weathering to brown. The 

 limestone suggests a marine origin for these shales, while the Carboniferous 

 of the basin is evidently a fresh-water deposit. Not a single marine fossil 

 has so far been found in the Carboniferous rocks, and no trace of limestone 

 beds has been discovered in them. (See footnote on page 381.) Under 

 these circumstances the Little Compton shales and the Newport Neck shales 

 must evidently be consigned to some other geological horizon. The only 

 other horizons so far determined by fossils in eastern Massachusetts are the 

 Olenellus and Paradoxides Cambrian and the Carboniferous. The Para- 

 doxides Cambrian has so far not shown the presence of limestone beds, 

 nor are the shales ever reddish. The Olenellus Cambrian shales are, how- 

 ever, often reddish, often include very thin limestone beds, and at all the 

 localities named include also limestone beds 6 to 8 inches in thickness. 

 This suggests the possibility of the Little Compton and Newport Neck 

 shales being of Olenellus Cambrian, or at least of Cambrian age. Of 

 course, the finding of fossils will afford the only certain means for iden- 

 tifying the horizons of these beds. 



QTJARTZITES OF NATICK. 



The quartzite on the northern side of Bald Hill, along the escarpment 

 northwest, west, and southwest of Natick, and at various points along the 

 road between Drum Rock Hill and Natick, has already been described in 

 connection with the general geology of the southern part of the Carbon- 

 iferous basin. These quartzites are, however, pre-Carboniferous. The 

 same may be said also of the quartzites occurring from Natick northward 



