636 General Notes, 
sediments of small thickness ; these sediments accumulated along 
the southern coast of the emerged land, but, as in Afghanistan, 
cover only a comparatively small area. Beds of lignite are abun- 
dant in the lower parts of the Trias-jura, as, for example, on the 
flanks of the Kara-tau and all around the Fergana basin, and in 
the absence of the true coal-measures, may prove of economical 
importance. The Jurassic is conformably covered by the Creta- 
ceous and Tertiary beds, which reach a thickness of 650 metres in 
Fergana, and even 1600 in Hissar. These two series are so inti- 
mately linked that it is impossible to fix a precise line of demarca- 
tion between them, and both alike have been affected by dislocations 
which are well-marked near the mountains, but die out in the 
centre. The Cretaceous series comprehends very varied rocks, 
those of the plains differing much from those of the Tian-shan, 
where they consist chiefly of marls and limestones, the latter often 
shelly, but becoming oolitic and compact more to the east; the 
marls often enclose gypsum. It is in Fergana that the Cretaceous 
‘presents the greatest diversity of faces, but as fossils are rare and 
in poor condition, it is difficult to separate the series into stages. 
GENERAL.—THE GEOLOGICAL STRUCTURE OF AFGHANISTAN, 
—M. Griesbach, Geologist of the Afghan Boundary Commission, 
has at various times published in the Records of the Geological 
Survey of India preliminary notes upon the geological structure of 
those portions of Afghanistan visited by him. These facts have 
been brought together by M. de Margerie in his Compte-rendu de 
Publications relatives à la Géologie del Asie et de P Amérique, in such a 
manner as to give what appears a tolerably clear picture of the geo- 
logical structure of this mountainous country. The principal crest 
of Afghanistan is formed by the Hindu-Kush and the Koh-i- Baba, 
the latter of which is continued into Persia, by chains running 10 
the northwest. Although the greater part of the country 18 a8 yet 
geologically unexplored, the researches of M. Griesbach are suffi- 
cient to afford a good index to the character of the remainder. It 
thus appears that the palæozoic and older mesozoic rocks only come 
to the surface on the line of the main axis, the rest of the country 
being occupied mainly by cretaceous beds, often unconformable to 
the older mesozoic beds upon which they repose. Extensive sur- 
faces in the north and west are covered by tertiary deposits. p 
region between the main chain of Afghanistan and the next noe 
important series of elevations, viz., that which runs llel pa 
Indus, is occupied by a number of anticlinal folds, crowded together 
in the region of Cabul, but spreading outwards 
approach the frontier of Persia. Most of t 
