The Conwy is bounded to the east by the rolling ancient
mudstone hills of the
Silurian period, the Migneint Moors. These acid rocks are generally covered in thin, often acid soils and for large parts of the
upland areas the cover is of
moor grass –
Mollinia spp and
Erica communities. As a result, the water entering the river tends to be acidic and often coloured brown with
humic acids. To the west, the catchment is underlain by older
Cambrian rocks which are harder and the landscape is, as a consequence, more dramatic with high craggy hills and
mountains, through which the river falls in cascades and
waterfalls. Examples of torrential river
geomorphology can be seen at
Conwy Falls and in the Lledr Gorge. The land to the east is highly forested with planted non-native
conifers. On the western side of the valley are a number of lakes and
reservoirs. The rocks are also rich in minerals and there are many abandoned mine sites where
copper,
lead and
silver have been mined since Roman times. The river valley downstream of Betws-y-coed is relatively wide and fertile, and supports
dairying and
sheep rearing. In the winter, these pastures are used to nurture the sheep brought down from the mountains to avoid the worst of the winter weather. ==SSSI==