FROM WEST PAKISTAN 91 



line (i.e. RN = o*445iZR + 5635*2) has been drawn on the graph. This is the 

 Correlation or Regression Line of the Rakhi Nala on the Zao River with parallel 

 dotted lines showing the standard error of estimate. 



(c) Conclusions 



The Palaeocene and Eocene of the Rakhi Nala section can be divided into five 

 distinct biostratigraphic units on the basis of Ostracoda. Two of these Units, I and 

 II, occur in the Palaeocene and three, III, IV and V, in the Eocene. Biostrati- 

 graphic Unit IV of the Rakhi Nala section is represented in the Zao River section 

 by at least 332 ft., and Unit V by 3743 ft. The Units in the two sections have almost 

 identical ostracod faunas. Biostratigraphic Unit IV of the Rakhi Nala is also 

 represented in the Shpalai Khwara section by at least 320 ft. 



The Equations of Correlation of biostratigraphic Unit V between the Rakhi Nala 

 and Zao River sections have been calculated by means of ostracod species common to 

 the two sections. From these two equations any point in one section can easily be 

 correlated with the corresponding point in the other section or vice versa, (see 

 Fig. 6). The standard error of estimate for the two equations has also been calcu- 

 lated. Since only the upper part of biostratigraphic Unit IV in the Zao River 

 section has yielded ostracods, only this part of the unit can be correlated with any 

 certainty. 



Eames' lithological units for the southern Sulaiman Range (Rakhi Nala and Zinda 

 Pir) extend into the northern part of the Sulaiman Range (Zao River and Shpalai 

 Khwara). This is particularly true for sediments from the Shales with Alabaster 

 (upper Lower Eocene) to the upper part of the Upper Chocolate Clays (upper Eocene) . 

 Sediments below the upper part of the Shales with Alabaster of the Shpalai Khwara 

 section are unfossiliferous except for a few horizons containing poorly preserved 

 pelagic foraminifera. These are 12,450 ft. thick and are probably equivalent to 

 Eames' Upper Rakhi Gaj Shales, Green and Nodular Shales, Rubbly Limestones and 

 lower part of the Shales with Alabaster. In the Zao River section sediments below 

 the upper part of the Shales with Alabaster are undifferentiated and are probably 

 unfossiliferous. This suggests that environmental conditions in the northern 

 Sulaiman Range during most of the Early Eocene were not suitable for abundant 

 marine life. 



The faunal breaks in the sections studied do not always coincide with Eames' 

 lithological subdivisions. For example, the Upper Rakhi Gaj Shales, Green and 

 Nodular Shales and Rubbly Limestones have a similar ostracod fauna and are 

 regarded as one ostracod biostratigraphic unit. Another example is in the Kirthar 

 Formation where a new fauna appears before a change in lithology. This occurs in 

 the uppermost part of the Lower Chocolate Clays (i.e. just below the White Marl 

 Band). Most of the species range from the uppermost part of the Lower Chocolate 

 Clays to the lower part of the Upper Chocolate Clays, although the White Marl Band 

 lies in between. 



The Palaeocene/Lower Eocene boundary in the Rakhi Nala section has been 

 drawn at the base of the Nummulites irregularis Limestone of Eames and Nagappa. 



