clojure.lang.Symbol cannot be cast to java.lang.String

gistfile1.clj

 (defpage "/boundary" {:keys [latitude longitude distance]}
  (resp/json (apply LatLong/bounding-box 
      (
        (fn [a b c]
          (map read-string '(a b c) ))
        latitude longitude distance)))
  )

; LatLong/bounding-box takes three arguments which should be numbers (though not necessarily ints)
; latitude, longitude, and distance are strings coming in and need to be numbers passed in