Clay dogs

Clay dogs are naturally occurring clay formations that are sculpted by river currents from glacially deposited blue-gray clay and then dried by the sun. They exhibit tremendous variety in shape and size, with some being simple and others having highly complex forms. They only occur in a few places in the world. Until recently, Croton Point along the Hudson River produced them, but the clay slope that produced the dogs was subsequently demolished to extend a park lawn.^[1] Clay dogs were described in detail in an article by L. P. Gratacap, Opinions on Clay Stones and Concretions.^[2]

References

1. Ward, Colin (1982). "Jane Jacobs and the Clay Dogs". Built Environment (Alexandrine Press) 8 (4): 229–231. Retrieved 18 January 2016.
2. Gratacap, L.P. (September 1884). "Opinions on Clay Stones and Concretions". The American Naturalist (University of Chicago Press): 882–892. Retrieved January 17, 2016.