1816.} Geological Society. 309 
the beds of which it is composed exhibit great irregularities, both 
with regard to their mineral composition, and the presence or ab-. 
sence of organic remains, 
Jan. 19.—A memorandum relative to the basaltic columns of the 
Isle of Salsette, by Mr. Babington, was read. 
The Island of Salsette is separated at its northern extremity from 
the adjacent Mahratta coast by a narrow creek, on the eastern side 
of which runs a low ridge of basaltic hills, for the space of four or 
five miles. Wherever the rock is uncovered, are traces of the 
columnar structure ; but in three places clusters of columns rise 
above the general surface, like so many bundles of reeds. The 
height of the most lofty columns is about 50 feet, the average dia- 
meter of each not exceeding 20 inches... The shafts vary in form 
from four to seven sided, and are not articulated. The rock is ex- 
ternally of a rusty brown colour, but internally is of a light bluish 
grey, withan irregular fracture, and not very compact. 
The western hills of Bombay exhibit traces of the same forma- 
tior. ; but the rock is much darker in colour, closer in its grain, of 
greater hardness and specific gravity. — 
A paper on the geology of the Lincolnshire wold, and the ad- 
jacent county, by Edward Bogg, Esq. was read. 
If a line of section be drawn from Saltileet, on the coast of 
Lincolnshire, through Louth and Wragby, to Lincoln, it will 
exhibit the following beds, proceeding from the newer to the older. 
The country between Louth and the sea is flat and marshy, and 
presents alluvial clay mixed more or less with sand and marine 
organic remains. From Louth to the high hills in Donnington, a 
distance of about five miles, the country is occupied by the elevated 
district of the wolds, which consists of beds of chalk, the upper 
of which are of a white colour, and contain subordinate beds of 
flint, while the lower are of a reddish colour, and are destitute of 
flints. Immediately below the chalk is a bed from six te 10 yards 
thick, of coarse brown pebbly sand without organic remains. To 
this succeeds a bed, 12 or 14 yards thick, of clay with subordinate 
beds of lime-stone, the structure of this latter oolite, and it con- 
tains nodules of pyrites and bivalve shells. Below this lies a stra- 
tum of sand, of various colours, from dark brown to light grey, 
inclosing thin beds of sandy limestone with organie remains ; the 
thickness of this stratum is considerable. The last of the series is 
a slaty clay, or shale, of unknown thickness; but which had been 
bored into for 100 yards, near the village of Donnington. It con- 
tains a multitude of beds of slaty clay, with marine remains, gene- 
rally soft, but sometimes considerably indurated, and often very 
bituminous, of iron-stone and of grit. The surface of this last 
bed is covered in many places with alluvial deposits of blue clay 
and of grey marl. 
