404 R. C. WALLACE 
the management of the Northwest Quarries Co. Ltd. The surface 
capping of drift is 8-10 ft. thick, and the bowlders are mainly lime- 
stone, very few Archaean granites or gneisses being found. Under- 
lying the drift are thinly and irregularly bedded limestones, 3 ft. 
thick, mottled in similar fashion to the more massive limestones 
underneath. Then follow 14 ft. of buff mottled limestone, wrought 
in ledges 3-6 ft. thick (Fig. 1). This is practically homogeneous, 
Fic. 1.—Upper Mottled limestone, Garson’s Quarry. Tyndall 
though certain horizons show the presence of cephalopods more 
markedly than others (see Fig. 2). Underneath is a blue mottled 
limestone, uncovered for 6 ft., the darker patches on the stone 
showing, even on the weathered surface, a darker blue color than 
on the buff stone. A bore has recently been sunk in order to deter- 
mine the quality of the underlying strata, and the manager of the 
quarry, Mr. Pfeiffer, has kindly supplied the following details. 
The blue mottled is altogether about 13 ft. thick. Underneath 
this lies a second horizon of buff mottled stone. The quarry and 
