568 DESCRIPTION OF THE 
more fully developed in the gorge, a short distance up the river, some of the beds pre- 
senting the amygdaloidal form, others the characteristics of the conglomerate. This 
is particularly well seen between the first and second falls of the river. The lower 
falls are about forty yards further up, with several small cascades between them. The 
water falls in that distance seventy-eight feet. At the second falls, the lower beds 
disintegrate with great facility. At the mouth of the river, an arch has been cut — 
through the amygdaloidal beds, on the left side, through which the river enters the 
Lake, when its mouth becomes blocked up by sand and gravel during the prevalence 
of storms, as shown by the sketch on page 367, taken by Dr. Owen, in 1848. 
Between the mouth and the first fall, the conglomerate is overlaid by twenty-five 
feet of grayish-coloured metamorphosed rock, and above that is a bed of trap, as 
shown in the following cut. The water falls twenty feet through a gorge eight feet 
a. Conglomerate. 
b. Metamorphosed 
sedimentary beds. 
c. Basaltie bed. 
=} 
in width. The metamorphosed rock gradually assumes a more compact character 
in the ascending layers, and finally graduates into an amygdaloid like the one 
underlying the conglomerate. 
One mile up the river, a bed of amygdaloid is overlaid by a very hard, compact 
rock (No. 211), which presents at some points a semi-columnar structure and a 
trappous appearance. It is, however, a metamorphosed siliceo-argillaceous shale, 
and seems to have some intercalated beds of argillaceous sand-rock. About two 
miles up the river, it forms narrow perpendicular dalles, the walls of which are 
forty feet in height. I estimated these shales to be two hundred and fifty feet in 
thickness. They are in layers from half an inch to two inches thick, generally of 
a red colour, but in some places gray; the upper part weathering easily, but be- 
coming- more compact in the lower beds, which are of a dark purplish colour, and 
amygdaloidal. 
Between the brecciated conglomerate and the metamorphosed shale, is a bed of 
coarse, dark-red trap, from fifteen to twenty feet thick, and conforming to the general 
dip of the rocks already named, which is southeast by south, at an angle of from 8° 
to 10°. Above this point, and beneath the trap, there occurs from two hundred 
and fifty to three hundred feet of a rock such as has usually been described under 
the name of volcanic breccia (No. 212). At the junction of this rock with a dike 
which crosses it, it presents every evidence of fusion, and resembles, in both internal 
and external characters, some of the breccias from extinct volcanoes of Italy and 
France. It is evident, however, that the great mass of material which enters into 
its composition, has been derived from sedimentary rocks, through which the molten 
trap has been forced, breaking them up, and reducing the fragments to a semi-fluid 
state. Beyond the dike, for the distance of a mile and a half, this rock is exposed 
