PILGRIM GEOLOGY OF THE PERSIAN GULF. 1. Persia. A great series of more or less massive limestones, with interbedded shales and sandstones, extends through the whole of Persia, resting on rocks of Cretaceous age,-either Hippuritic lime stone or the volcancis of the Gulf region. Except nummulites the formation, where I saw it, was generally devoid of fossils, or at all events of fossils in an identifiable condition. The nummulites even. are not particularly numerous except in certain beds, and are often. not in a matrix from which they can be conveniently extracted for purposes of identification. Systematic search for nummulites and careful observation of the stratigraphical relations would no doubt throw considerable light on the precise age of different portions of this limestone massif, and even enable us to map geologically the country over which it extends, but during my rapid traverses I was unable to accomplish anything of the kind. The most complete section I saw of these beds was in the Bakhtiyári mountains on the Ahwaz-Ispahán road between Dehdiz and the bridge over the river at Shalil. Here some 6,000 feet of the series are exposed, resting on a thick bed of bluish shales which Loftus considers to be Cretaceous; beneath this is Hippuritic lime stone. There is no unconformity to be detected in this section between the Cretaceous and the Nummulitics; they are both tilted at an angle of from 30° to 50°, but seeing that in other places, where I observed a junction between the two, the shale bed is not always present, there must evidently have been erosion of the Cretaceous before the Nummulitics were deposited. Moreover, the lowest beds of this section are characterized by an abundance of Nummulites lævigatus, which implies that they correspond in age to the upper most beds of the Lower Khirthar of Baluchistan and Sind, or perhaps even to the Upper Khirthar according to Vredenburg's¹ views on the zonal distribution of the Indian nummulites. The Numinulitic rocks at Shalil cannot therefore be older than middle lutetian. 1 E. Vredenburg: Rec. Geol. Surv. Ind., XXXIV, p. 87, 1906. For the identification of this as well as of the other nummulites collected by me in Persia and Arabia, I am indebted to Mr. E. Vredenburg's kindness. 18
