Abstract: An upstanding tubular housing is provided mounted in sealed connection to the lower end of a tubing string as a downward extension thereof and encloses a screen sample tube therein for movement between an upper limit position with the lower end of the tube closing a center bore formed through a cone point on the lower end of the housing and a lower limit position with a major portion of the length of the screen tube downwardly projected through said center bore. A drop rod is downwardly insertable through the tubing string and engageable with the upper end of the screen tube for downwardly displacing the latter from its upper limit position to its lower limit position and the drop rod is tubular and defines an upward extension of the interior of the screen tube.