That fact can be explained by the similarity in their genes.
Dogs and coyotes are from the same class, family and genus (Mammalia, Canidae, Canis). This is almost enough for their offspring to be viable. But if the DNA is similar (which it is) offspring the chances of viable and fertile offspring is high almost at 100%.
Sedimentary rocks are formed overtime are different particles of sand, shells, pebbles and other fragments of materials form layers and harden into rock.
