At Kingswood, upstream from the old weir, is Martley’s highest (seasonal) waterfall, when running a charming little beck that tumbles out of the vale between the hills of Aymestry, Wenlock, Ludlow Shale, and most locally Coalbrookdale Formations (you can read more about each of these on Wikipedia). The water is high in dissolved carbonates that precipitate out on exposure to the air and coat objects with layers of tufa.
Ian found the illustrated sheep’s jaw bone

BGS Geology Viewer (LINK) says the following about Coalbrookdale Formation:

Mudstone. Sedimentary Bedrock formed approximately 423 to 428 million years ago in the Silurian Period. Local environment previously dominated by shallow lime-mud seas.

Setting: shallow lime-mud seas. These rocks were formed in warm shallow seas with carbonate deposited on platform, shelf and slope areas. With fluctuating sea levels some sediments were washed off the land and deposited as mud interbedded with the carbonates.