1.- A PRELIMINARY STUDY OF SOME SANDBIAN (UPPER ORDOVICIAN) GRAPTOLITES FROM VENEZUELA INSTITUTO GEOLOGICO DE ESPAÑA; MADRID; ESP, 2011 ORDOVICIAN OF THE WORLS Ver registro 2.- THE STRATIGRAPHIC DISTRIBUTION OF GRAPTOLITES IN THE CLASSIC UPPER MIDDLE ORDOVICIAN UTICA SHALE OF NEW YORK STATE:AN EVOLUTIONARY SUCCESSION OR A RESPONSE TO RELATIVE SEA-LEVEL CHANGE? 1998 Ver registro
