156 
Returning to the railway track a good section is exposea 
in a cutting near the switch. First the cherty beds of the 
Trenton are seen, then the heavier-bedded strata of the 
over-lying Tetradium zone, and, resting on the latter, the 
thin and shaly beds of the Prasopora zone. ‘The fossils of 
this zone are very common here, and also at the “Heap”, 
a small pile of debris at the right a few rods farther down 
the track. 
MONTREAL ROAD. 
Trenton, Black River, and Pamelia.—A powder maga- 
zine is situated near the Montreal road two and a half 
miles (4 km.) from Ottawa. A quarry south of the 
magazine shows a section of strata which belong at 
a horizon just at the top of the crinoid beds and 
just below the Prasopora zone. From the presence of a 
species of Jetradium in abundance, these have been 
termed the Tetradium beds. This is the typical locality 
for Tetradium racemosum, and specimens can be obtained 
in the thin, pure layers in the upper part of the quarry. 
There is a small fault through the quarry, which causes a 
downthrow of the beds to the north. In the face of the 
quarry toward the powder magazine, can be seen a reef of 
Stromatocertum. 
Between this quarry and Montreal road a fault brings 
the highest beds of the Trenton and the Utica down in 
contact with the Tetradium beds. The Utica is exposed 
just at the corner where this road joins the Montreal road. 
The Robillard quarries, which are situated in the same 
beds just seen at the powder magazine quarry, have been 
worked very extensively, but contain very few fossils other 
than Stromatocertum and Solenopora. 
Northward beyond these quarries is another quarry 
showing the upper beds of the Pamelia formation, from which 
it is possible to collect specimens of Onchometopus simplex, 
ostracods, and a few brachiopods. A part of the way 
down the hill, just below the house, is a bed of creamy 
white sandstone, which is the base of the upper division 
of the Pamelia, and contains many pelecypods, Isochilina 
armata, and a few gastropods. At the foot of the hill is 
the Aylmer sandstone. 
Returning toward the Montreal road, at a point where 
the road rises over a low escarpment, with a small quarry 
