HASWELL— ON THE DENUDATION OF AETHUE's SEAT. 93 
lines of growth. In a young state the shell is longitudinally ribhed, the ribs being 
tumid and close together; uo trace of this is seen iu the adult. 
A second specimeu, probably of the same species, is rather larger, 
and has a rib between the suture and the marginal angle, and six 
primary ribs on the body-whorl. 
Both these examples are distorted by pressure. The smaller ex- 
ample (figured) is compressed Literally. The rock is a very hard 
chalk, much resembling some of the lighter-coloured clay concretions ; 
fossils are yellowish. 
(:') Fusps. 
This form differs from the Brighton specimens chiefly in the large number of equal- 
sized ribs, a character to which little importance can be given ; it may be varietal, but 
more probably is but an adult ornament, just as are the longitudinal ribs, a feature pecu- 
liar to the young. The lip is a little inflected. The space between the posterior two 
ribs appears to have supported a sharp projecting keel, now brokeu away. 
SOLAKIUM BlNGHAMI {Baily). 
Shell thick, much depressed, not half so high as wide; composed of about six whorls, 
which very gradually increase in size. The upper side of the shell is a greatly depressed 
cone ; the under side a large conical hollow. The whorls are five-angular ; they are 
attached by one side, two converge interiorly to form the base, one perpendicular forms 
the side of the shell, and the fifth forms the slightly oblique upper surface. 
This last form of the upper surface of the whorl is ornamented mar- 
ginally by upwards of forty tubercles, wliich are elongated in a 
direction at right angles with the line of growth. A second row, 
more numerous and much smaller, passes round near to the suture. 
Both the interspace and tubercles are finely striated spirally. The 
perpendicular side is not more than half the width of the outer basal 
space ; it has on its lower margin a row of tubercles similar to that 
on its upper margin, but they are narrower and half as numerous 
again. The tubercles so entirely occupy the side that the groove 
between the two rows is not half so wide as either of them. The 
outer part of the base is very finely cancellated ; the angle it makes 
with the inner half is nodulated with seventeen large tubercles. 
The inferior suture is much more impressed than tlie superior one, 
and the sutural margin of the base is ornamented with a row of 
tubercles, about as numerous as that on the upper margin of the 
side. The umbilicus is nearly as deep as wide. 
ON THE DENUDATION OF AETHUE'S SEAT. 
By James Ha swell, M.A. 
" Quid magis eat saxo durum ? quid moUius unda ? 
Dura tamen molli saxa cavantur aqua." 
The condition of Central Scotland during the long period repre^ 
