The scraping of leather against leather, the hollow clatter of stone and shale, the rustle of whatever creature settled behind her.
This time, she paid no attention to the shale or placing her feet right.
Olentangy shale 20 35
Holdenville shale 260
They are at a depth of about 12 ft., in slaty shale containing Llandeilo fossils and contemporaneous felspathic ash and scoriae.