ROGERS—-WESTERN INDIA. 123 
laterite is the same in age and composition as the laterite of western 
India. Their difference has already been pointed out by Newbold 
and Aytoun ; and that in Madras may be presumed, for the following 
reasons, to be of a much later date than that of Bombay, probably 
only a lateritic or ferruginous conglomerate. The laterite of Bombay 
overlies the great trap formation at all elevations of from less’ than 
a hundred feet above the level of the sea in the country round the 
Gulf of Cambay to 5000 or 6000 feet above it on the highest Ghaut- 
level. In connexion with the Turkeysur nummulitic rocks, Mr. 
Wynne, in his Report on the Geology of the Surat Collectorate, 
speaks as follows :— 
“A low range of hills rises near this town and stretches south- 
wards towards the Taptee ; they are formed of ferruginous or lateritic 
beds intercalated between agate conglomerates, and, having a low 
dip to the west, they pass beneath the limestone just mentioned 
[grey nummulitic], which, however, is traceable along their flank 
and reappears in the Taptee river at the end of the range, being let 
down by a fault to a lower level, but preserving its westerly dip, 
and seen to be overlain again by another band of laterite.” 
Here it appears that laterite is both below and above Nummulitic 
limestone. There can thus be no doubt that this laterite belongs to 
the Lower Eocene. ‘The rocks of the Nummulitic series near Gulla 
on the Taptee, at the distance of a few miles south of Turkeysur, 
are reported by Mr. Wynne to overlie those of the latter place, and 
are thus a little higher in the Eocene. ‘The laterite in the neigh- 
bourhood of Turbhan, to the south-east of Surat, is described in the 
same report as compact and brecciated, and as being of a very similar 
character to that just mentioned. There seems to be no doubt 
that this laterite is precisely similar in mineral character to that of 
the Deccan, which caps the western Ghauts or Syhadree range, 
Mahableshwur, &c., frequently at the top of precipitous scarps 
thousands of feet in height above the level of the low country of 
Goozerat. There is no apparent reason for supposing that the 
laterites of the high and low levels are referable to at all widely 
separated geological ages, the evidence of the agate conglomerates 
near Turkeysur, intercalated between lateritic beds, being the only 
proof of the rock having been deposited at different times. 
Mr. Blanford, in reporting on the age of the traps, admits that 
denudation must have taken place to an immense extent after the 
Nummulitic rocks were deposited; and the rare occurrence of laterite 
in the low country may probably be attributed to this. Subsequent 
upheaval, too, is proved by the position of the lateritie beds to the 
south of Gogo; these have been broken up from below, and lie as 
they were thrown over on the flanks of some of the hilis. This 
might account for the disruption of the Island of Perim from the 
mainland; but only a much more violent action would have sepa- 
rated the laterites of the high and low levels, supposing them to 
have been deposited under similar geological circumstances. This 
rock, again, appears at precisely the same level on the opposite sides 
of valleys in the Concan and Deccan, giving ample proof of denuda- 
