UnityClick.cs

using UnityEngine;
using System.Collections;

public class UnityClick : MonoBehaviour {

    public LayerMask terrainLayer;

    void Update()
    {
        if ( Input.GetMouseButtonDown(0))
         {
             RaycastHit hit ;
             Ray ray = Camera.main.ScreenPointToRay (Input.mousePosition);

             if (Physics.Raycast(ray, out hit, 100.0f, terrainLayer))
             {
             Debug.Log(hit.point);
             }
         }
    }


}