MANSFIELD: ROXBURY CONGLOMERATE. 99 
attached to its occurrence even though it lies in a critical position with 
reference to the two basins. The evidence furnished by the valley 
of the Neponset River, apparently excavated in weak rocks which 
appear to pass from the northern to the southern basin, is equally 
suggestive and unsatisfactory. While therefore there seems to be 
reason for believing that the two basins are connected, the existence 
of the connection cannot be definitely established from the evidence 
now at hand. 
The Narragansett sediments are characterized in some of their 
members by a considerable intensity of red color. In this respect 
they greatly exceed the Roxbury series and generally also the rocks 
of the Norfolk Basin. They consist of arkoses, coarse and fine con- 
glomerates, shales, and sandstones. In general appearance they are 
much like the rocks of the Boston and Norfolk Basins but they are 
more highly fossiliferous and in some parts of the series are marked 
by fossiliferous pebbles and by pebbles containing a considerable 
amount of white mica. Muscovitic rocks are not known to be repre- 
sented in the Roxbury and Norfolk Basin series. Here again sediments 
of similar character but of different ages are found in close proximity 
‘to each other but fortunately the fossils contained in them furnish 
means of identification. 
The sediments of the Parker River Basin, so far as known, occupy 
but a small area in comparison with that represented by the series 
already mentioned. According to Crosby (b, p. 267-268), they appear 
to consist largely of slate but there.is some schistose conglomerate 
resembling that at Milton or at South Natick. They are accompanied 
by igneous breccias and amygdaloid in somewhat the same manner 
as are the rocks of the Boston Basin. Their color, however, is more 
intense than that of the Roxbury series in general and more closely 
resembles that of the strata exposed at South Natick and at Charles 
River Village. 
The Bellingham Conglomerate occupies only a small area a few 
miles northwest of the Narragansett Basin. It is believed by Crosby 
to be the stratigraphic equivalent of the Harvard Conglomerate and it 
has undergone remarkable deformation, whereby the pebbles have 
been elongated into spindle-shaped and pencil-like masses (ibid., p. 
148). 
At Harvard, Mass., a wedge-shaped area of conglomerate not more 
than a few hundred feet wide at its broadest part extends about two 
miles south from a little north of the center of the town. The pebbles, 
consisting of quartzite and argillite, are flattened, bent, and drawn 
