PART 1.] 
Annual Report for 1874 . 
9 
its own research. But the difficulty in compiling a general map does not depend so 
much on the size or frequency of these gaps or lacuna, for, of course, they could be left out>' 
to he filled in afterwards, but on the fact, that without some knowledge of these inter¬ 
vening spaces, it is impracticable to correlate the rocks in one part of the country with 
those elsewhere. Each district or area examined in itself is necessarily described by itself, 
the rocks which occur in it are reduced to a system, their succession traced out, and their 
relations one to the other determined so far as possible. Local distinctive names are given 
to such separate groups, and all is rendered as complete as may be possible for that area. 
The survey operations are meanwhile directed to some other locality, and the same process 
of examination is gone through, but the results are not exactly the same ; new sub-divisions 
of the rocks become necessary, new names are given to distinct groups, for local convenience 
of description. This result is equally correct and equally satisfactory for its own area. But 
for any general map, it becomes essential that all these differences should he eliminated, how¬ 
ever roughly, and all reduced to one general system or scale, and this is precisely what 
it is impracticable to do without some knowledge, however imperfect, of the country generally* 
which knowledge there is no means of obtaining while the officers of the survey are engaged 
in isolated localities and on special reseai’ches. 
Seeing then the very distant prospect which was before the survey of being able to work 
out any general map from their own researches, I have for some years devoted much atten¬ 
tion to preparing separate descriptions and in some cases separate maps of certain divisions 
of the country, so far as these were possible. Passing over papers descriptive of tho general 
geology of districts, or collectorates, (such as Surat, Gwalior, neighbourhood of Madras, 
Godavari, &c.,) a general sketch of the Geology of the Central Provinces was given so 
long since as 1871, of Orissa in 1872, of the Bombay Presidency in 1872, of the North- 
Western Provinces in 1873, of part of Punjab in 1873, and a general sketch of the Punjab 
is now just ready for press, while a general sketch of Bengal will betaken up also. These are 
all iu addition to the regular and more detailed descriptions of separate areas, coal-fields, &c.* 
<fcc. The most cursory' reference to these sketches will show the impossibility of combining 
all into one system, without more knowledge of the intervening areas, as yet unexamined, 
or, as the other alternative, reducing the map to such large generalities as would get rid of 
the e minor difficulties, hut would at the same time make such a map of extremely little value. 
It is our earnest hope, however, that the survey will he permitted to complete such a 
general sketch map as may T prove useful and within a limited time. 
Publications. —Of the Memoirs of the Geological Survey of India, Vol. X, part 2, 
announced as nearly ready at the close of last season, was issued early in the year. This 
contained a descriptive account of the Geology of Pegu by Mr. Theobald, with map, &c. 
Aud at the close of the year, part 1 of Vol. XI, containing a report by Mr. Mallet on the 
Geology of Darjiling and the Western Dhuars, with two geological maps, &c., appeared. 
Of the Records of the Survey, the usual quarterly publication was steadily maintained, 
and the volume for 1874 contains no less than twenty-three separate papers on varied points 
in the Geology of India. Four of these are valuable summaries of the geological results 
obtained during the visit to Yarkand with the mission recently returned from that country 
by our lamented colleague, Dr. F. Stoliczka. These with the note on the Altum-Artush, 
which will be found below, complete all that ho had brought into shape for publication. Of 
practical papers, there are notes on the iron ores of Kunaaon: on the raw materials for iron 
smelting: on Petroleum in Assam: on the subsidiary materials used in production of artifi¬ 
cial fuel: on the building and ornamental stones of India: on Potash salts: on Manganese 
ore, &c., &c., while descriptive notices are given of parts of Northern Hazaribagh ; neighbour¬ 
hood of Murree; of Kangra; of the Garo hills; of the Luni Puthan country west of Sind, 
