IS 
SILURIAN 
It resembles much the carboniferous British species, B. 
corm-arietis, or rather the young* state of it, which has been 
called B. navicula by Swerby. 
Locality .—Chorhoti Pass, 17,000 feet. (1744.) 
GASTEROPODA. 
MURCHISONIA HIMALENSIS. 
Plate 2, fig. 9. 
M. parva vix semiuncialis, brevis, anfractibus 3—4 depressis tri- 
costatis. Costae acutae aequidistantes, centralis tricarinata ; areae in- 
termediae valde concavae striatae. Basis abbreviata. 
Depressed, not half an inch long. Spire of few whorls, 
which are not much oblique, and are ridged by three very 
strong concentric ridges. The central one, or band, marked 
by three ribs, forms the central and quite prominent ridge; 
and the upper and lower keels, at equal distances from the 
central one, alike prominent, thin, and somewhat wavy. The 
facets between them are very concave, covered with sharp and 
tolerably regular lines of growth, which do not bend much 
backward to the band,—are nearly vertical below it, and re¬ 
treat but little as they pass over the blunt short base. The 
space above the upper band is rather broad and quite horizon¬ 
tal. The young whorls do not differ much from the older 
ones. 
Locality .—Chorhoti Pass, 17,000-17,500 feet. (Nos. 
1737, 1744.) 
MURCHISONIA PAGODA. 
Plate 2, fig. 10. 
M. semiuncialis, elongata, anfractibus 4—5 sejunctis, valde angu- 
latis, carina centrali ct inferiori instructis. Carina subcentralis emi- 
nentior, inferior remota projecta, spatio intermedio concavo. 
Turreted, of four or five whorls; the spire elongate, the 
whorls rather oblique, much separated, and sharply angular 
