There are few natural waterbodies of any size in Wales; Snowdonia is home to most. Besides Llyn Tegid, a few lakes (Welsh: llyn, plural llynnoedd) occupy glacial troughs including Llyn Padarn and Llyn Peris at Llanberis and Tal-y-llyn Lake south of Cadair Idris. Llyn Dinas and Llyn Gwynant and Llyn Cwellyn to the south and west of Snowdon feature in this category as do Llyn Cowlyd and Llyn Ogwen on the margins of the Carneddau. There are numerous small lakes occupying glacial cirques owing to the former intensity of glacial action in Snowdonia. Known generically as tarns, examples include Llyn Llydaw, Glaslyn and Llyn Du'r Arddu on Snowdon, Llyn Idwal within the Glyderau and Llyn Cau on Cader Idris.