A new lithostratigraphic unit, Venado Formation, Ordovician in age, is proposed. The stratotype is exposed on the western flank of the Colombian Eastern Cordillera, along the highway bordering the Venado river, a tributary of the larger Cabrera river (Huila Department). The exposed section has been divided into three units: the lowermost one, with predominantly gray micaceous shales; the middle unit, or Venado Formation, as we design it, is a thick sequence (670 rn) of interbedded feldespathic and light green micaceous sandstones; the uppermost unit contains feldespathic sandstones, conglomeratic lithic sandstones and polymictic conglomerates, with hummocky beds. Lithology and sedimentary structures point out to the deposition of the Ordovician sequence on a siliciclastic platform under fine and bad weather. The storm waves, episodic, non-periodic events, were produced probably by meteorological phenomena. The stratigraphic column of Rio Venado shows a prograding sequence; its age and geographic position may indicate the retreat of the Ordovician sea during the Llanvirnian time, or the previous epoch to the post-Llandeilian / pre-Emsian hiatus. A new lithostratigraphic unit, Venado Formation, Ordovician in age, is proposed. The stratotype is exposed on the western flank of the Colombian Eastern Cordillera, along the highway bordering the Venado river, a tributary of the larger Cabrera river (Huila Department). The exposed section has been divided into three units: the lowermost one, with predominantly gray micaceous shales; the middle unit, or Venado Formation, as we design it, is a thick sequence (670 rn) of interbedded feldespathic and light green micaceous sandstones; the uppermost unit contains feldespathic sandstones, conglomeratic lithic sandstones and polymictic conglomerates, with hummocky beds. Lithology and sedimentary structures point out to the deposition of the Ordovician sequence on a siliciclastic platform under fine and bad weather. The storm waves, episodic, non-periodic events, were produced probably by meteorological phenomena. The stratigraphic column of Rio Venado shows a prograding sequence; its age and geographic position may indicate the retreat of the Ordovician sea during the Llanvirnian time, or the previous epoch to the post-Llandeilian / pre-Emsian hiatus.