Arkell.1956.Jurassic..

406 RANGES OF SOUTH-EAST ASIA
SPITI AND NITI
The famous locality of Spiti is a small isolated area, only 40 miles long
in the direction of strike and less than half as wide, surrounded by extensive
tracts of Triassic and Palaeozoic rocks. The Niti area, rather more
than 100 miles farther south-east along the strike, is somewhat larger.
Both Jurassic outcrops are relics of dissected synclines within the
Himalayan Mountains north of the main crystalline range.
From ancient times splendidly preserved ammonites were brought
down by traders to be sold to Hindu pilgrims in the holy places of India.
They were called Salagrams and were used as charms. The first to discover
their source in the Spiti Shales were the Strachey brothers, but it was a
long time before geologists elucidated the stratigraphy or collected any
ammonites in situ. The earliest collections were formed by purchase and
exchange, and the figures of isolated specimens by Gray, Oppel (1863)
and Salter & Blanford (1865) (the first and third revised by Crick, 1903,
1904), gave rise to lively polemics among leading specialists of the day,
especially between Neumayr and Nikitin. Stoliczka (1866) and Griesbach
(1891) laid the groundwork of the stratigraphy, and Hayden (1904)
published a more authoritative account of the Spiti area, correcting
mistakes made by Stoliczka owing to inaccurate palaeontology.
In both areas the Upper Triassic and Jurassic rocks consist of a thick
mass of dark grey or black limestone (Kioto Limestone, 150-700 m.),
overlain conformably by the Spiti Shales (about 90-150 m.). The Kioto
Limestone forms forbidding cliffs along the valleys of the Spiti and other
rivers, while the Spiti Shales tend to weather into black, rolling, bare
downs. The Kioto Limestone is almost unfossiliferous, except locally
near the top.
The first, and still the only, attempt to collect ammonites in place from
the Spiti Shales was made on an expedition in 1892 sent specially to
investigate the stratigraphy of the Mesozoics of what is here called the
Niti area (Johar and Hundes). It was sponsored by the Geological Survey
of India who sent their officers, Middlemiss and Griesbach, accompanied
by C. Diener of Vienna, who took part at the instigation of Professor E.
Suess. In his account of this expedition, Diener (1895, pp. 582-8) first
named the three divisions of the Spiti Shales already recognized by
Griesbach (1891, p. 76), in ascending order the Belemnites gerardi Beds,
Chidamu Beds and Lochambel Beds (both after places in the Niti area),
and the collections made are still the main basis of our knowledge of the
ammonite succession. The ammonite fauna of the Spiti Shales was later
monographed by V. Uhlig (1903-10) and exhaustively discussed by him
from every aspect (1910a). The other mollusca were monographed by
Holdhaus (1913).
The charge can never be brought against the British that during their
occupation of India they either neglected scientific opportunities or kept
a corner in scientific investigations. The splendid series of palaeonto-
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