56 ALEXANDER MURRAY ON THE 
Carboniferous age are the latest of the older systems, and are spread unconformably over 
the Laurentian and Silurian strata alike. The system consists of limestones, slates, and 
sandstones, and is exhibited over wide areas on each side of St. George’s Bay; and again 
near the centre of the island in the valleys of the Humber River. The presence of the 
lower members of the system at the Magdalen Islands appears to indicate the axis of an 
anticlinal fold, in which case we may suppose a trough of the higher measures, including 
the great body of sandstone, to exist on the south-east side of a line drawn from the Mag- 
dalen Islands to the vicinity of Cape St. George, occupying the sea bottom between that 
line and the south-west coast of Newfoundland. Again, the Exploits River below Red 
Indian Lake flows generally nearly on the strike of a set of graptolitic slates of the Hudson 
River group, till nearly reaching the Grand Falls, where it intersects the sandstones and 
traps of Middle Silurian age ; and thirdly, the course of the Great Gander River runs upon 
a set of soft metamorphic rocks, consisting of mica slates, serpentines, and Middle Silurian 
strata, from near its sources to its exit Into Gander Bay. These three great arteries main- 
tain a remarkable parallelism in the direction of their courses, bearing generally between 
N. E. and N. N. E., as also do many of the smaller streams, such as the Indian Brook of 
Hall’s Bay (the valley of which is simply a continuation of the valley of the east branch 
of the Humber), the Gambo, and Terra Nova of Bonavista Bay, and several others. But 
there is a vast number of streams and rivulets, besides the tributaries of the great drainage 
waters, whose courses are transverse to that bearing, cutting across older and harder meta- 
morphic formations, which descend in short turbulent torrents, alternating with expanses of 
still water, which frequently open out into large and picturesque lakes and ponds. 
The geological map will further show that nearly the whole peninsula of Avalon, be- 
sides a large area of the mainland at the south-eastern end of the island, is occupied by 
rocks of Huronian age, which are succeeded by Primordial or Cambrian strata, resting un- 
conformably on the basset edges of the former; the terminal outcrops skirting the shores 
of Conception and Trinity Bays, and forming all the larger and more important islands 
within these bays, and extending across the mainland from Trinity Bay to the shores.of 
Bonavista Bay in a tolerably broad belt. 
In the Huronian or Intermediate system, a band of a dark brown cr blackish clay slate 
oceurs about 2,000 feet thick, which is frequently ripple-marked, and contains the curious 
little fossil described by the late Mr. E. Billings, who named it Aspidella Terra-novica ; as 
also a form recognized by the same author as Arenicolites spiralis; these bemg the only 
organic remains hitherto found in the whole system (See Geol. Sur. of Nfld., pp. 144, 145). 
In consequence of the softer quality of this part of the formation, it has yielded more 
readily to denuding forces, and usually gives a greater spread of flattish or reclaimable 
ground than is found over the areas occupied by the strata either above or below. The town 
and settlements around St. John’s are chiefly situated upon these Aspidella slates, as are 
also most of the chief towns and villages of Avalon, while the larger streams for the most 
part flow more or less in valleys where the same rocks are distributed. 
With these few remarks upon the strata which apparently have been chiefly 
affected by the more modern denudation, I shall leave it to the geological map to explain 
the rest of the general distribution, and pass on to the orographically colored map, recently 
published on a scale of seven miles to one inch, which will show the general contour of 
