East-west trending ridges, up to four miles long and ranging in width from 50 feet to nearly a mile, break the flat topography of the Bearpaw Shale outcrop in the Lake Basin area. Similar but distinctly separate masses of sandstone, overlying siltstone and overlain by marine shale, are ripple marked and cross bedded. A recent road cut reveals the distinct channel nature of the sandstone which contains plant remains and lignite and mud balls. These features and the reconstructed outcrop pattern indicate a deltaic environment with distributary channels.

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