YOU SAID:
She finds seashells by the seashore
INTO JAPANESE
彼女は海岸で貝殻を見つける
BACK INTO ENGLISH
She finds shells on the coast
INTO JAPANESE
彼女は海岸に貝を見つけた
BACK INTO ENGLISH
She found a shell on the coast
INTO JAPANESE
彼女は海岸にシェルを見つけた
BACK INTO ENGLISH
She found a shell on the coast
That didn't even make that much sense in English.