82 
HAYOEN: GEOLOGY OF SPITI. 
A few bivalves also occur in the shales ; they belong to the genus 
Halobia, and closely resemble H . fascigera, Bittner. 
It is probable that these " Juvavites shales " correspond to the 
" Halorites beds " (Diener), from which they differ, however, in the 
apparent absence of both Halorites and ParajuvavHes, neither of 
which genera has been found at this horizon in Spiti. 
The shales are overlain by a massive, grey — at times white and 
dolomitic — limestone, chiefly composed of corals. 
Coral limestone. 
It forms a very characteristic horizon throughout 
Spiti and Rupshu, but has not been recognised in Kumaon or in 
Garhwal. The commonest fossil is a coral resembling Lithodendron, 
the presence of which led Mr. Griesbach to regard the limestone as of 
rhaetic age.^ A few gastropods were found in this bed in Rupshu, and 
brachiopods in Spiti ; the latter are rare, but include — 
Spiriferina griesbachi, Bittner; and 
(?) Rhynchonella hambanagensis, Bittner. 
Consequently Dr. von Krafft believed that this limestone represented 
the "beds with Spirijerina griesbachi " of the Painkhanda sections. 
Ihe coral limestone is overlain by arenaceous limestones and sand- 
stones, passing up into a series of calcareous shale, 
Morotis shales. , 
which in iithoiogical characters strongly resem- 
bles the " Juvavites beds." This subdivision, the thickness of ^vhich 
is about 300 feet, contains an interesting fauna, composed almost 
entirely of bivalves and brachiopods, which occur chiefly in the upper 
part of the series : they include— 
Monotis salinaria, Bronn. 
Anodontophora griesbachi, Bittner. 
Spiriferina griesbachi, Bittner. 
Rhynchonella bambanagensis, Bittner. 
Aulacothyris joharemis, Bittner. 
Spirigera dieneri, Bittner. 
Monotis salinaria, which has been found in almost all sections 
ot these beds in Spiti, occurs in a band which varies from 6 to 8 
Inches in width and lies at about 100 feet below the top of the series. 
* Memoirs, G. S. I., vol. XXIII, p. 220. 
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