Dr. H. Preiswerk—Oil Region of the Northern Punjab. 13 
The occurrence of oil is therefore closely related to special 
geological features. It occurs only in the boundary region between 
the Hill-Nummulitic limestone and the Upper Nummulitic (Kuldana 
beds). It appears on the surface only where the beds have a normal 
position and a moderate inclination (below 60°). This is especially 
the case in places where the Nummulitic limestone dips axially 
under a closed cover of clays and marls of the Upper Nummulitic. 
The oil-bearing bed is chiefly cavernous, marly limestone, and 
partly gypsiferous marls. 
2. SAIDPUR-RATTA HOTAR. 
Oil-springs. 
The oil-spring of Ratta Hotar is situated § mile north-west of the 
end of the Tonga Road from Rawalpindi to Nurpur Shahan, and 
a few hundred yards east of the park and the graves, where a 
Mohammedan priest resides. On the topographical map (1 inch = 
1 mile) the place is marked by the name “Gugul pani”. Along 
a little channel there are outcrops of a disturbed limestone mingled 
with oil-bearing marls 20-30 yards long and a few yards broad. 
At the spring itself there is a hole from which water issues covered 
with thick oil. The oil flows drop by drop. The flow of the oil is 
said to be somewhat stronger in the dry season. 
Geological Features. 
The Section Ratta Hotar.—Section VI, Plate I, shows the geological 
situation of the oil-spring at Ratta Hotar. 
The oil-bearing rock: the limestone lenses with interstratified 
clayey marls form the contact-layers between the compact 
Nummulitic limestones and the gypsiferous variegated clays of the 
“ Upper Nummulitic’”’. These lenticular limestones are also found 
elsewhere in the upper parts of the Nummulitic limestone. They 
are widely developed near Murree, and there also they are bituminous 
for long distances. I have found them again in typical development 
in the Eastern Salt Range between the Nummulitic limestones and 
the Murree sandstones, but there they were free from bitumen. 
A few metres south of the oil-springs the massive Nummulitic 
limestone is exposed, forming a steep ridge and dipping north 
An OBO 
To the north of the oil-rocks follow the typical variegated gypsi- 
ferous clays of the Upper Nummulitic. These dip north a little less 
steeply (about 65°). 
To the east of the oil-springs sandstones appear between the oil- 
rock and the marls. They arealso represented in Section VI, Plate I, 
although they are not visible at the oil-spring itself. I suppose 
these sandstones to form a synclinal core of Murree beds. 
By the outcrops inSection VI of Rattar Hotar the existence of two 
anticlines with two corresponding synclines is proved. 
The anticlinal cores consist of Nummulitic limestones, the 
