GEOLOGICAL HISTORY OF THE ST. JOHN RIVER. 283 
the entire absence of marine fossils, sufficiently attest the operation of fresh waters at that 
time, as well as the general rapidity and wide distribution of the currents by which its area 
was traversed. In the lower-carboniferous and Devonian ages we have what would seem 
to be more positive proofs of the existence of such channels at very early periods. 
The first of these evidences is to be found about twelve miles above the city of Freder- 
icton, where the stream, after intersecting the great central granitic axis, sweeps in the form 
ofa broad crescentic curve across the highly disturbed Lower Silurian slates which flank this 
axis on the southern side, producing a trough, a mile or more in length, of no great width, 
and bordered for most of its length by perpendicular bluffs, on one side, at least, a hundred 
feet or more in height. While these bluffs are composed of nearly vertical strata, and con- 
sist chiefly of very hard quartzose rocks, there may be seen at their base, in direct contact 
with, and, as it were, plastered against their cut edges, a series of beds of wholly different 
character. They are horizontal, or nearly so, and in colour, as well as in other features, are 
readily recognizable as a portion of the lower-carboniferous formation, so largely displayed 
around the border of the coal-basin only a short distance south. From the position and 
relation of these beds the inference was drawn that the gorge described must have been in 
existence in the lower-carboniferous period, and as it was then partly filled and obliterated 
by the marine sediments of the period, it must have owed its origin to some earlier era of 
emergence and hence to some fresh-water stream, of which this portion at least coincided 
with the modern river. 
That the period in question was that of the later Devonian is regarded as probable, 
both from the relations of the beds of this era to those of the lower-carboniferous, indicat- 
ing that the principal surface-features of the region had been determined prior to the latter, 
and also, from the character and distribution of the Devonian fossils, proving the existence 
of a wide-spread terrestrial flora. In one instance, at least, the mode of occurrence of the 
latter is such as to point directly to the existence of considerable fresh-water streams at the 
time of their accumulation. 
The case in point, first noticed by Mr. G. F. Matthew, is found in the peculiar features 
presented by the Devonian rocks of the Lepreau basin, about twenty miles westward of St. 
John, where the coarse and irregularly-bedded sandstones which there make up the bulk of 
this formation are remarkable for containing large trunks of fossil trees (Dadozylon), now 
largely anthracised, in such numbers and at such positions as to indicate that they were 
drifted logs, brought down by some large stream during a period of flood, and imbedded in 
the sand bars about its mouth. Where this stream had its source, and whether or not it 
was in any portion of its course coincident with the present valley of the St. John, may 
be a matter of conjecture. It may, however, when taken in connection with the facts 
already stated, be fairly regarded as affording proof of the existence of a distinct drainage- 
system in this portion of New Brunswick at least as early as the latter part of the Devo- 
nian era. 
As to periods earlier than the Devonian, the comparatively limited extend of dry land, 
the paucity of hill-ranges, and the general prevalence of marine conditions, were all unfavor- 
able to the development of river-systems, and there is no reason to suppose that this part of 
North America differed materially from others in this respect. Indeed the abundance of 
marine fossils met with along large portions of the district traversed by the St. John, both of 
Upper and Lower Silurian age, sufficiently attest this fact. The influence of these more 
