380 J. D. Dana — Archoean axes of Eastern iV". America. 



V. The Central-Newfoundland Range : extending over 

 a broad region east of the Exploits River Valley, to the east 

 side of Exploits Bay. 



Besides these ranges there appear to be two other more or 

 less complete ranges separating pairs of bays that head together, 

 and then, the easternmost, that of Ferryland. 



The Troughs. — The troughs into which the country is topo- 

 graphically divided by these ranges were the rock-making 

 troughs or basins of Paleozoic time, and partly of Mesozoic, 

 and were more or less independent in their geological his- 

 tory, especially after the Lower Silurian era. The Lower 

 Silurian and Cambrian beds often spread from one of these 

 troughs to another, and across the protaxis, over portions that 

 were then submerged. But the mountain-making disturbances 

 at the close of the Lower Silurian ended in giving greater 

 height and breadth, and Siluro-Cambrian annexations, to the 

 Archaean, not only in the Green Mountain region, but also, as 

 evidence from unconformabilities proves, in the Mt. Desert 

 and Acadian ranges ; and probably in others. 



The troughs or areas between the ranges above enumerated, 

 are the following. 



A. Between Ranges I and II, The Connecticut Valley 

 Trough : containing, Lower Silurian, Upper Silurian and 

 Devonian beds in the state of metamorphic schists (mica, horn- 

 blendic, chloritic) and crystalline limestones, but nevertheless 

 affording fossils of each of the eras for their identification ; and 

 containing also, the Connecticut Valley Sandstone or Jura- 

 Trias beds, which are uncrystalline and fossiliferous. 



B. Between Ranges II and III, the Gaspe-Worcester 

 Trough : extending from Gaspe, on the Bay of St. Lawrence, 

 over much of rforthern New Brunswick and central Maine, and 

 continued to Worcester, Mass. and possibly beyond; and con- 

 taining Cambrian ? Lower Silurian, Upper Silurian, Devonian 

 and Carboniferous beds. The rocks are unaltered at Gaspe, but 

 become more or less metamorphic in southwestern Maine and 

 graphitic slates and mica schists of Carboniferous age at Wor- 

 cester, these last being identified by fossil plants. 



C. Between Ranges III and IV, the Acadian Trough : 

 beginning in northern Newfoundland west of the northern 

 part of Long Range and extending to St. George Bay and 

 Cape Ray, in southwestern; passing thence over the region of 

 the Magdalen Islands, in the Bay of St. Lawrence to Nova 

 Scotia and New Brunswick on either side of the Bay of Fundy ; 

 and thence to the region of Boston and Massachusetts Bay, and 

 to that of Narragansett Bay in Rhode Island ; and including 

 rocks from the Cambrian to the Jura-Trias as identified by 

 fossils. The rocks are metamorphic to the south. Strata from 



