SYSTEM OF NORTHERN MAINE. 37 
through these Silurian sandstones may be found the remains of branching plants, while 
at one point, in close proximity to the siliceous beds first described, is a small exposure of 
quartzose rock containing an abundance of what are evidently Psilophyta, apparently 
undistinguishable from those found by Mr. Robb near the mouth of the river. As the 
conglomerates in which the latter occur are not unlike those described above as forming 
part of the Silurian succession, and as the plant-bearing beds above Shaw’s Mills are 
almost certainly of this age, it is at least possible that all these rocks are really Silurian 
rather than Devonian, as some of them have been supposed to be. 
I now pass to the region of the Fish River lakes in Northern Maine. 
The description of the rocks found in this vicinity, as given in Hitchcock’s “ Report on 
the Geology of Maine” (1861, pp. 420-424) is from the pen of Prof. A. 8. Packard, jun., who, 
however, does not himself express any opinion as to their age. Among these rocks the 
most interesting is a band of highly fossiliferous limestone, outcropping on the western 
shore of Square or Sedgewick Lake, and which has to some extent been locally employed 
as a source of lime. From collections made at the locality by Packard and Hitchcock, the 
late Mr. Billings succeeded in recognizing about forty distinct species, of which fourteen 
were new, while my own visit to the locality, though short, enabled me to obtain a some- 
what greater number, including, as determined by Mr. Ami, two additional species not 
hitherto described. These fossils have been regarded, both by Mr. Billings and Mr. Ami, as 
being of Lower Helderberg age, and the enclosing beds, in this as in other respects, may be 
regarded as the counterpart of the limestone beds of the Beccaguimic region, in New Bruns- 
wick. Associated with these beds on Square and Eagle Lakes, and apparently enclosing 
them, there are, as described by Packard, ledges of red shale and conglomerate, with beds of 
grit, the conglomerates containing fragments of dark slate and jasper, and dipping 45° to 
the northward, in which direction they are followed, first, by bufl-weathering fossiliferous 
sandstones and then by dark clay-slates, which, with other slates and sandstones, occupy 
the remainder of the country northward and eastward to the St. John River valley. A like 
succession was observed on the thoroughfare from Portage Lake, a few miles west of Hagle 
Lake, and at Ashland. All the rocks of the above section have been regarded by Prof. 
Hitchcock as Devonian, and are so represented in his map of Northern Maine, as they are 
in that accompanying the last edition of Sir Wm. Dawson’s “ Acadian Geology.” If how- 
ever the above relations are as supposed, it would seem altogether probable that the great 
bulk of strata here met with is, as on the Beccaguimice, of Silurian rather than Devonian age. 
I may add, from personal examination, that in almost every particular the beds of the 
Fish River lakes bear the closest resemblance to the beds which accompany and enclose 
the limestones. of the Beccaguimic valley. 
It is true that no graptolite-bearing beds were here observed, but beds of very similar 
character occur, while even on the Beccaguimic these beds are but thin. Moreover, in both 
instances the sandstones exhibit the same peculiar Lower Carboniferous aspect. Both 
contain similar remains of crinoids and shells, mingled with stems of plants, while the 
conglomerates in both are also alike in containing numerous fragments of black slate 
associated with others of bright green and red jasper. If to this we add the fact that, 
beneath the conglomerates, etc., above described, we have, on the shores of Portage or 
Nadeau Lake, connected with the other or westerly branch of Fish River, a well defined 
