EXPLANATION OF PLATES. 
PLATE 1. 
Two views of basalt exposure at Division Street and Mallon Avenue, Spokane. Two 
distinct flows are here represented. At the point marked (x) in the lower picture a 
portion of a trunk of Sequoia sp. was found between the flows. 
PLATE 2. 
Upper right: Photograph of cavity in basalt nearly filled with crowded spherical 
bodies of second-generation siderite. Upper left: Photograph of small cavity in 
basalt showing crystals of cristobalite associated with rods of feldspar and small 
masses Of first-generation siderite. Enlarged 6 diameters. Lower: ‘‘Caterpillar-like 
form’’ produced by alignment of closely crowded units of siderite. Natural size. 
PLATE 3. 
Upper: Thick coating of transparent colorless hyalite opal overlying small globules 
of first-generation siderite. Lower: Pseudomorph of limonite and goethite after 
large individual of second-generation siderite. Natural size. 
