24 
dark grey. In some layers the rock breaks with a conchoidal 
fracture and weathers into irregular nodules. The Lowville 
portion is on the whole lighter in colour than the Leray beds* 
In the lowest layers, exposed at Rockland, it is inclined to split 
into thin sheets. The massive, fine-grained, light grey bed in 
the upper part of the Lowville which forms so definite a feature 
in the Rockland exposure is undiminished in thickness at 
Ottawa, but it was not found in the MacLaren Landing section, 
although both the zone made up of almost solid Tetradium and 
the layer characterized by worn gastropods are present. 
The Chazy beds are included in the MacLaren Landing 
section only. The limestone is on the whole much more impure 
that that of the beds above it. The uppermost exposed layer is 
purer than those below, and of a lighter grey colour. Below these 
beds appear interbedded strata of somewhat greenish lime- 
stones intermingled with more sandy layers. There are frequently 
red-brown streaks at a fresh fracture. Gradually the impure 
limestones give place downwards to shales. At the old quarry 
the chief fossil content of the thin limestones is ostracods. The 
base of the section is composed of a very impure, mud-coloured 
limestone, and shales often arenaceous. About a third of a mile 
west of this section, along the shore, the underlying Chazy beds 
of shale and sandstone are brought to the surface by the eastern 
tendency of the dip. No fossils were found in these beds, whose 
thickness it is difficult to ascertain as they extend out into the 
river. Where exposed they appear to have the general southerly 
and easterly dip. 
