166 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
felsite near North Attleboro. The account of these features is included 
under the heading “Relations to Igneous Rocks” on page 233. 
Sandstone and Shale. The coarse sandstones or grits contain in 
addition to quartz a considerable amount of feldspathic and felsitic 
material. In the finer sandstones the rock is more quartzose. White 
mica is an abundant constituent. The shales are sometimes arena- 
ceous or carbonaceous and are often fossiliferous. Usually, however, 
they are argillaceous and fairly compact. 
The grains of the sandstones are variable in size ranging from tiny 
particles to fragments three-eighths of an inch in diameter. In the 
specimens examined the grains were chiefly angular and subangular. 
None were rounded. ‘There was little arrangement of the particles. 
The cement was usually silicious. 
The colors of the finer sediments are generally grays, sometimes 
with tints of green but often shading to dark or gray black. Reddish 
and purplish colors are also important and especially characteristic of 
specimens from the northern parts of the basin. 
The bedding is not well displayed in the hand specimens. ‘The 
features observed in the field are set forth in the next chapter. 
Summary of the Narragansett Basin Series. (1) The arkose of 
the Narragansett Basin is much more decomposed than that of the 
Boston or Norfolk Basins. 
(2) The matrix of the conglomerate agrees in texture and general 
composition with that of the Norfolk and Boston Basins, but it con- 
tains more carbonaceous material and is characterized by the abun- 
dant occurrence of white mica. 
(8) The pebbles of the conglomerate consist largely of quartzite, 
felsite, and granite. The striking features are: — the occurrence of 
fossiliferous quartzite pebbles and pebbles of muscovite granite; the 
more frequent occurrence of the fossiliferous pebbles and the greater 
coarseness of the conglomerate toward the south; the remarkable 
deformation of the pebbles at the Fogland Point and Purgatory 
localities. 
(4) The finer sediments are often fossiliferous and carbonaceous 
and are characterized by an abundance of white mica. 
(5) The colors of the conglomerates are usually grays with greenish 
and sometimes reddish tints. The sandstones and shales are gener- 
ally grayish to black. Specimens from the northern part of the basin, 
whether of conglomerates or finer sediments are usually of a red color. 
Tore HARVARD CONGLOMERATE:— Matrix. The matrix of the 
