Dr. H. Preiswerk—Oil Region of the Northern Punjab. 5 
Between the Nummulitic limestones at the base, and the immense 
sandstone beds following next above, there occurs with great 
regularity that very formation in which we find the oil-springs. It 
is called “‘ Upper Nummulitic ’ by Wynne, and may be homotaxial 
with the “ Kuldana beds”’ of Middlemiss.1 It contains variegated, 
chiefly red or brown, clays and marls with gypsum and layers of 
porous or compact limestones and beds full of Nummulites and 
Assilina. Cellular limestones (cargneule) are often found at their 
base, forming the top of the compact Nummulitic limestone. In 
some parts these Upper Nummulitic beds have a thickness of several 
hundred metres. 
The plateau of Rawalpindi (see Plate I) itself consists of red and 
gray sandstones, reddish clays, and conglomerates in the younger 
parts. These formations represent the middle and upper Tertiary : 
the Murree beds and the Siwalik group. We find them everywhere 
in the environs of Pindi, unless they are covered by the often thick 
conglomerates and loess-like formations of the diluvium and 
alluvium. 
The separation between limestone hills on the one hand and the 
sandstone region of the plain on the other is not absolutely sharp : 
bands of sandstone occur also as synclines infolded with the lime- 
stones, such as the sandstone district of Sang-Jani, and also 
Nummulitic limestones rise as anticlines out of the sandstone region 
of the plain. Such “ outliers ” (Wynne) are e.g. the limestone hills 
north of Kutbal, which form the eastern branch of the Chitta Pahar 
range. They continue to the east as the anticline of Golra, which 
near Saidpur comes closer again to the Nummulitic limestone hills. 
At Golra and at other places in this advanced anticline the massive 
Nummulitic limestones of the anticlinal core disappear below the 
variegated gypsiferous marls of the Upper Nummulitic. It is in 
these very places that the oil-springs appear. Precisely the same 
tectonic features give rise to the oil-springs of Gunda, near 
Fatehjang. 
A yet more striking and isolated outlier is the Kairi-Murat 
ridge, south-west of Rawalpindi, where the Nummulitic lime- 
stone of the anticlinal core rises out of the plain as a steep and long 
limestone ridge. At the east end of the ridge the Nummulitic 
limestone sinks in the axis of the anticline below the marls of the 
Upper Nummulitic, and these farther east below the sandstones of 
the Murree beds. Here, too, the oil appears above the Nummulitic 
limestone as soon as it is covered by the Upper Nummulitic clays. 
All the Tertiary formations of the environs of Rawalpindi are 
intensely folded and squeezed together into tightly compressed 
folds. The dip is almost always very steep, and in the axes of the 
folds isoclinal structure is frequent. In the limestone ranges we 
find here and there overthrusts to the south. The sandstones of 
a 
1 Memoirs Geol. Surv. of India, vol. xxvi, 1896, p. 42. 
