27 - Shape of the Deposits. The larger deposits are thin, flat-lying sheets of nearly uniform depth from’ the surface to the underlying sand or clay. The surfaces, which are from 1 to 2 feet higher than the surrounding valley floors, are broken up into nearly circular humps full of radiating cracks resembling the_top of a cauliflower (Plate IV). The tops of these humps are, as a rule, from 1 'Geolog ical Suryey, Canade Areas with hydromagnesite of 00d quality. 1,2,3- Exposures of hydromagnesite of good quality. 4,5,6.- Exposures of calcite with gypsum. 7- Exposure of gypsum with calcite. &- Exposure of conglomerate overlain by travertine. > Tunnels % Prospects Areas with deposits of impure hydromagnesite. Scale of feet 2000 ° 41000 3000 4000 Approximate magnetic declination, 27 “Fast Figure 3. Hydromagnesite deposits near Clinton, Lillooet district, British Columbia. to 2 feet higher than the ground between them. In certain places along the edges of the deposits, as at Meadow lake and elsewhere, lunar or cusp- shaped cavities filled with large basaltic boulders, but with practically no fine-grained material, lie between the cauliflower-like humps. The shapes