"When the 'till' is removed from the underlying rocks, these almost invariably show either a well-smoothed, polished, and striated surface, or else a highly confused, broken, and smashed appearance."[2]
Gratacap says:
"'Crushed ledges' designate those plicated, overthrown, or curved exposures where parallel rocks, as talcose schist, usually vertical, are bent and fractured, as if by a maul like force, battering them from above. The strata are oftentimes tumbled over upon a cliff-side like a row of books, and rest upon heaps of fragments broken away by the strain upon the bottom layers, or crushed off from their exposed layers."[3]
The Rev. O. Fisher, F. G. S., says he
"Finds the covering beds to consist of two members--a lower one, entirely destitute of organic remains, and
[1. "Geological Survey of Wisconsin, Iowa, and Minnesota," p. 147.
2. "The Great Ice Age," p. 73.
3. "Popular Science Monthly," January, 1878, p. 326.]
{p. 53}
generally unstratified, which has often been forcibly INDENTED into the bed beneath it, sometimes exhibiting slickensides at the junction. There is evidence of this lower member having been pushed or dragged over the surface, from higher to lower levels, in a plastic condition; on which account he has named it 'The Trail'."[1]