Conglomerate.

Conglomerate.

This specimen is from an outcrop of conglomerate in the Hafren forest, near Llanidloes, Mid Wales. The age of the rocks are Silurian, and they are in the Landovery epoch. The outcrop is markedly graded, with material at the top being very fine, and at the base very rubbly. The rock specimen is 10 cm. and the conglomerate layer is about 2 metres in depth. The conglomerate is very rich in quartz, with quite a number of large rounded pebbles at the base.and with smaller, often fractured pebbles towards the top.