270 Reviews — C. L. GrieshacWs Central Himalayas. 



Conformably succeeding the Haimanta rocks in the sections 

 between the parallel ranges of the Central Himalayas, is a series of 

 shaly qnartzites alternating with coral limestones about 300 feet in 

 thickness, which, on the evidence of the fossils, are referred to the 

 Lower Silurian, and resting on these are quartzite beds about 1000 

 feet thick, which are placed as Upper Silurian, although the fossils 

 in them have not yet been fully determined. 



Next in ascending order are dark limestones, about 650 feet in 

 thickness, containing Corals, Crinoids and Brachiopods, which are 

 doubtfully placed as Devonian ; following these are red crinoidal 

 limestones considered to be Lower Carboniferous and white qnart- 

 zites and dark limestones with Productus, belonging to the Upper 

 Carboniferous. In Spiti, limestones containing Athyris royssii, Fro- 

 ductas, etc., probably represent the highest beds of the Carboniferous 

 in this region. 



According to Mr. Griesbach's experience, there is a gradual 

 passage between the diiferent Palseozoic formations in the Hima- 

 layas, and from the phyllites and quartz shales of the Haimantas or 

 Cambrian, to the Upper Carboniferous, there is a perfect and con- 

 tinuous sequence without the slightest unconformity. There are 

 evidences of considerable physical changes at or near the close of 

 the Carboniferous period, and the strata of this age are in places 

 unconformably overlapped by shales with Productus, considered 

 to be Permian. The interruption between the Carboniferous and 

 Permian is followed by another long interval without a break, 

 which continued until after the deposition of the Liassic limestones. 



The Permian Productus shales, not over 250 feet in thickness, are 

 followed by the lowest beds of the Triassic series containing Otoceras. 

 This series in the Northern range of the Himalayas consists mainly 

 of limestones, dolomites and shales, in all about 4000 feet in thick- 

 ness. The resemblance between the Triassic rocks of this region 

 and the Alpine facies of the same formation, long since recognized 

 by Salter, Strachey and Suess, is confirmed by Griesbach, who 

 divides this series into Lower, Middle, and Upper, corresponding 

 respectively to the Bunter, Muschelkalk, and Keuper of Germany. 

 The Rhsetic series of the Himalayas consists also of limestones and 

 dolomites, and resting on them are shelly limestones of Liassic age, 

 having a thickness altogether of 2000 to 2500 feet. As in the 

 Triassic, there is also in these Ehgetic and Liassic rocks a very 

 strong resemblance to the cojTesponding formations iu the Alps, not 

 only as regards the fossils, but in lithological character as well. 



There seems to be an unconformity or interruption between the 

 Lias limestones and the next succeeding Spiti shales, which contain 

 Ammonites and other fossils of Middle and Upper Jurassic type. 



Kesting on the Jurassic Spiti shales there are sandstones and 

 shales with Belemnites probably of Cretaceous age. Above these 

 are light-grey limestones with Upper Cretaceous marine fossils, 

 which are exposed in sections north of the Niti Pass, and in other 

 passes across the watershed between the Ganges and the Sutlej at 

 elevations between 16,000 and 18,000 feet above the sea. 



