392 REV. THOMAS BROWN ON THE MOUNTAIN LIMESTONE AND 



tion, and that I have submitted the whole to Mr Satter, Palontologist to the 
Government Survey, whose assistance has been of special importance, not only — 
from his great eminence in that science, but from his familiarity with the fossils 
of England and Ireland. Thesystem of nomenclature in his hands being uniform, 
we can employ the species here named with confidence as points of comparison 
with distant formations. A considerable proportion of the following list are new 
to Scotland. Two or three of the names are given on the authority of Dr FLemine; 
the rest on that of Mr Satter. 
. Fossils. 
Corals.—The following seem the most common species : — 
Chaetetes tumidus, L. fasciculata. 
Aulophyllum fungites, Zaphrentis species. 
Lithostrotion junceum. } 
To these may be added (from the Bryozoa), the Fenestella plebea, which is 
plentiful in all the strata. 
Shells.—From the bed F at Ardross, I obtained the following, viz. :— 
1. Lingula mytiloides. 7. Nucula attenuata, 
2. Productus semi-reticulatus. 8. Macrocheilus ovalis. 
3. Pecten Sowerbii. 9. Bellerophon Urii. 
4. Edmondia unioniformis. 10. Bellerophon decussatus, 
5. Schizodus sulcatus. 11. Nautilus subsulcatus, 
6. Nucula gibbosa. 12. Orthoceras cylindraceus, 
Along with these there were other species belonging to the following genera 
not yet determined, Orthoceras, Schizodus, Arca, Modiola, Loxonema and — 
Gontotites. Of the whole perhaps the shells most characteristic of the bed are a — 
strong handsome Schizodus, and a thin stiletto-like Orthoceras, whose long, taper 
form does not seem as yet to have been figured or described. | 
Fig. 1. 

—S 3 
1. Right Valve. 2. Left Valve. 8. Outside of Left Valve. 
Of the Schizodus, figures are here given from characteristic drawings furnished - 
by Mr Sauter. 
