Palaeontology serves the petroleum geologist in three ways; for correlation over short distances, for facies delimitation, and for age determinationwhich is another name for long-range correlation; it is however a valid distinction, since this is palaeontology's unique function. In the Tertiary rocks this function is best subserved by the planktonic or pelagic Foraminifera; and a comparison of the ranges of some Tertiary pelagic Foraminifera in the Middle East and in the Gulf Mexico-Caribbean Sea regions is made by means of a chart. Some synonymies, and other notes, àre appended.
La paléontologie sert au géologue pétrolier de trois façons: pour la corrélation à faible distance, pour la délimitation des faciès et pour la déterinination d'âge - qui est un autre nom pour la corrélation à grande distance; la différenciation a cependant un sens vu que c'est justement là l'unique but de la paléontologie.
Dans les roches du tertiaire ce but se trouve le mieux servi par les foraminifères planktoniens ou pélagiques; aussi la communication présente-t-elle, au moyen d'un tableau, une étude comparative de l'extension verticale de quelques foraminifères tertiaires pèlagiques dans les régions Moyen-Orient et Golfe du Mexique-Mer des Caraïbes.
On y a joint quelques synonymes et d'autres notes. Acknowledgements I wish to thank the Iraq Petroleum Company Ltd. for their kind permission to publish this note. I am happy to acknowledge a debt to Martin F. Glaessner, to whose private report for the said company * Senior Micropalaeontologist, Iraq Petroleum Co., Ltd., 1917-50; N.V. De Bataafsche Petroleum Maatschappij, The Hague, Netherlands, 1951.
I have had access; for, by independently reaching conclusions similar to my own, he has provided welcome support and encouragement.
Mr. G. F. Elliott has most kindly checked over the draft for me, and supplied helpful information on various questions.
I Palaeontology has long been recognized as an useful adjunct of petroleum geology, its best publicized aspects being as an aid in well-to-well or field-to-field correlation, and-again as an aid-in facies delimitation. In both of these roles it has sometimes been regarded as merely a special branch of sedimentary petrology, although in its palaeobiological aspect it really transcends this definition. In any event, its subordination to the position of a petrological accessory affects its dignity rather than its importance.
In a wider sense, however, correlation is rightly accorded a greater significance, insofar as it involves comparison with a standard geological column accepted throughout the world. Such correlation may be termed "age determination"-with the qualification that "age" is here expressed in iinits somewhat less precise than the historical calendar, and comparable with "dyna
