102 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
The conglomerate at Harvard is intimately associated with the 
so-called phyllite, which is graphitic in a number of places and at 
Worcester contains the coal mine in which a Lepidodendron was found. 
The Worcester phyllite is therefore considered Carboniferous and the 
Harvard Conglomerate is believed by Emerson, who has worked in 
the Harvard region, to be also of Carboniferous age.! 
No reliable data are at hand with reference to the ages of the Woon- 
socket, Bellingham, and Parker River Conglomerates. The only clues 
are furnished by their lithological resemblances to the other conglom- 
erate formations of the region. 
It is thus seen that the Narragansett and Norfolk Basin sediments 
are definitely known to belong to the Carboniferous period and that 
there is a strong presumption that the Roxbury series is of similar age. 
In the case of the outlying conglomerate masses there is no definite 
evidence, but it seems likely that these rocks may also be Carboniferous. 
Unity or Diversity of Origin. In view of the close lithological 
resemblance of the Roxbury Conglomerate to the sediments of the 
Norfolk and Narragansett regions, the basin-like occurrence of each 
group of strata and the known Carboniferous age of the Norfolk and 
Narragansett rocks, it seems unlikely that the separate sedimentary 
areas could have had diverse modes of origin. On the contrary, since 
the entire area in which these rocks lie is relatively small, it seems 
probable that similar causes operated to produce similar results in 
each case. Moreover, since the more westerly areas are possibly also 
of Carboniferous age it may be true that they too have been formed 
by similar agencies. The Roxbury Conglomerate has been the writer’s 
chief study, but its history is perhaps similar to that of the other areas 
and is thus of more than local significance. The data furnished by 
the other areas may in turn throw light on the history of the Roxbury 
Conglomerate. Therefore an account of the origin and structure of 
the Roxbury Conglomerate must take into consideration the neighbor- 
ing similar formations. 
Broad and Narrow Terrane Views. Whatever may have been the 
agencies that produced the conglomerates the latter may be conceived 
either as material originally deposited in separate, circumscribed areas 
or basins of not-much greater extent than those they now occupy, or as 
uneroded remnants of a great formation that has largely been removed. 
The former view implies an ancient topography not very different 
from that of the present time, while the latter involves the uplift and 
1 Conversation with the writer. 
