sand and mud for miles and miles

.
"Quick , Ju!", he cried. "We're close to the sea. I can hear it! Listen! That's where they've went. P'raps we can catch them if we was in time. They didn't mean to go without us. They've only forgot." "Iss", said Judy. "They've only forgotted. Less go to the sea." (...) He took Judy by the hand, and the two ran hatless in the direction of the sound of the sea. (...) They climbed another dune, and came upon the great grey sea at low tide. Hundreds of crabs were scuttling about the beach, but there was no trace of Papa and Mamma, not even of a ship upon the waters -- nothing but sand and mud for miles and miles. (Rudyard Kipling; "Baa baa black sheep")
.