XXXIX.--Geological Notes on part of Mazunderan

C. M. BELL
1840 Transactions of the Geological Society of London  
TEHRAN stands on an alluvial plain consisting chiefly of debris of limestone and trap rocks, (see Map, p. 381.) The high range immediately to the north of the city is composed of fine-grained lithographic limestone* ; the strata dipping to the north and resting upon porcelain-stone, which passes into serpentine and porphyretic claystone f. The hills to the south-east of Tehran and overhanging the ruins of the city of Rai, are formed of limestone reposing on trap. From Tehran the soft,
more » ... the soft, lithographic limestone extends nearly to the village of Demavend; but the sandstone of the subjacent coal-formation is occasionally exposed. A little to the westward of the village, the ground rises considerably ; and in the ranges of mountains, both north and south of the road, as far eastward as the caravanserai of Dalee chaee, nothing is seen but limestone resting on trap. In the bed of the river, we passed some upraised strata of altered shale,resembling coked coal; and upon the opposite bank we observed a loose conglomerate of fragments of limestone and trap, imbedded in what appeared to be dried mud, or detritus of the above-mentioned limestone J. * This stone, which takes a beautiful surface, has lately been used in the lithographic presses at Tehran; and it forms an excellent cement under water. Associated with a blue variety it extends over an immense tract to the N. and N.W. of Tehran, on the southern aspect of the chain of Elboorz. It there generally rests upon shale and red sandstone, which again overlie a compact limestone. (This rock is considered by the author to be mountain-limestone.-ED.) f The rock which forms the substratum of the greater part of the range of the Elboorz is trap, passing into every possible variety of basalt, greenstone, claystone, claystone-porphyry, pitchstone, pitchstone-porphyry, serpentine, &c. J From its appearance in different parts of the country, I imagine this formation to be the remains of great volcanic floods of mud, which carried along large fragments of rock, and were spread unequally over the surface; and that they have been more or less removed by denudation. In the present route, we met with it in several places, occupying low hills and valleys, in general unconformably with the strata beneath; and in other parts of Persia we found a similar formation covering the lower grounds, near lofty ranges of limestone elevated upon trap,-for instance, in the valley of the at Heriot-Watt University on March 6, 2015 http://trn.lyellcollection.org/ Downloaded from
doi:10.1144/transgslb.5.3.577 fatcat:2lemiaibnnfv5m3ojfhsd3nhc4