Geology and Paleontology. 637 
come more accentuated. North of the main axis lie a series of par- 
allel folds, narrow and lofty near the centre, but gradually spread- 
ing as they recede from it until they become broad and low undu- 
lations. ‘The geological structure of Persia seems to be a continu- 
ation of that of Afghanistan. The oldest fossiliferous deposits as 
yet known belong to the Carboniferous system. Wherever exam- 
ined, the Carboniferous outcrops are, like all the great bands ex- 
tending from Armenia to the Himalaya, of marine origin. Above 
the Carboniferous beds lie a number of conformable deposits com- 
posed of marine beds alternating with littoral and fresh-water lay- 
ers enclosing lignite and abundant remains of terrestrial plants. 
The exact classification of these beds has not yet been attempted, 
but they are surmounted conformably by undoubted Neocomian 
deposits, and their lower schistose portion is regarded by M. Gries- 
ach as representing the Permian and Lower Trias; while Jurassic 
fossils have been discovered in the upper part. Great eruptive 
rial seems to have characterized the end of this series of litto- 
ra x 
molluses found in it. The Niagara shales themselves can, upon ` 
evidence, yet Homalonatus reaches its maximum size after a 
Cælosteus feroz is the name given by Prof. Newbe ] 
s y Prof. Newberry to a large 
oa of fish, apparently allied to Dendrodus and Rhizodus, ot 
ch the Jaws, teeth and bones were discovered in the Lower 
