Publicaciones Geolo_gicas Especiales Del lngeominas

ZONATION OF THE CRETACEOUS OF CENTRAL COLOMBIA BY AMMONITES 3
Many thanks to Professors J. de Porta and
M. Julivert for their valuable suggestion and al·
ways encouraging example. I also want to thank
Professor Robert Hoffstetter who called to my
attention the importanc..of attending afoteign
Institution for advanced studies; to Dr. Jesus A.
Bueno [former Thechnical Director of the Mi·
nisterio de Minas y Petroleos of Colombia), to
Dr. Andres Jimeno rformer Director of the
Geological Survery o{ Colombia 1 who gave me
their support from the beginning of this investigation;
to Dr. Ramiro Lobo [Chief of the Conservation
Branch of the Ministerio de Minas y
Petroleos of Colombia 1 for his cooperation in
obtaining a loan for my graduate studies at
Berkeley.
I have to thank the Universidad Nacional
de Colombia, the Institute de Especializaci6n
Tecnica en el Extranjero (ICETEX) and the
Scholarship Division of the Organization of the
American States (OEA) for their economic sup·
port to complete my researches. Financial sup·
port for the plates included herein was provided
by the Fondo Colombiano de Investigaciones
Cientfficas y Proyectos Especiales "Francisco
Jose de Caldas" (COLCIENCIAS).
I have to acknowledge Professors W.B.N.
Berry, D.A. Savage, J. T. Gregory, C.M. Gilbert,
for their willingness to be member of my com·
mittee; thanks are also due to Dr. Ralph W.
Imlay and again to Professor Charles M. Gilbert
for their willingness to serve on my thesis .committee.
Many friends have shared with me their
ideas and also their skill in field work, of them
G. Renzoni, D. Barrero and C. Caceres-Giron
should not be blamed for my errors. Several
friendly field aides, Messrs. C. Giraldo, H.
Peiia, A. Aleman, J. Higuera, J. Duarte, had to
bear with my stubborn insistency to work
under changing weather conditions or had to
carry the heavy load of unprepared fossils. L. F.
Peii.a, and J. Garzon were very useful in helping
with the preparation of the fossils, I
thank them also.
ll.ACKNOWLEDGMENTS
The following institutions are acknowledged
for their gracious loan of specimens for
comparison: Museum of Paleontology, University
of California, Berkeley [Mr. J. Peck, Jr.],
Museo Geologico, lnstituto Nacional de Investigaciones
Geologico Mineras, Bogota, Colombia
rProf. L. F. Rincon and former Director Dr.
A. Alvarez]; the University of Michigan, the
Texas Christian University and the Academy of
Natural Sciences of Philadelphia; the British Mu·
seum (Natural History). Dr. J. Helms of the
Humboldt • Universitat in Berlin, DDR; provi·
ded me with excellent photographs of H. Karsten's
original material.
I have to acknowledge two old classmates
of mine, deceased Geologist Pedro Carvajal,and
Geol. Dip!. Ruben D. Llimis, who unafraid
backed with their wealth my loan from
ICETEX; Mrs. Amparo Prada was most helpful
in my dealing with the OEA.
Many thanks to Mrs. Gloria C. de Campos
and Mrs. Ines E. de Torres, who did the compo·
sing operation of the final version of the
manuscript. I thank Mr. Carlos Ruiz for his
assistance in improving the quality of the
text-figures.
The author could not have published this
paper had it not been for the compelling interest
of Dr. Alberto Sarmiento-Alarcon, and
especially Dr. Michel Hermelin, Director
Institute Nacional de Investigaciones Geologico
Mineras (INGEOli;JINAS).
I have a deep debt to Professor J. W. Durham
for his highly valuable scientific advise, his
thoughtful interest and his thoroughly under·
standing of my purposes during my studies at
Berkely.
In no way I am holding anybody except
myself, for any heresy I may have fallen into.
I hope this study, as simple as I see it, to
be acceptable to my family, my teachers, my
friends and to those who preceded me in the
study of the Cretaceous of Colombia. If this
work is found to be useful to my own country,
then I will be really pleased.