Weight per cubic foot in lbs.

Granites and Syenites ....

162 to 187

Trap and Basalt ....

164 to 187

Slate ......

165 to 181

Sandstones .....

116 to 170

Marble ......

168 to 172

Limestones, Compact ....

155 to 172

,, Granular ....

116 to 151

„ Shelly granular

130 to 140

Shelly ...

157 to 167

,, Magnesian ....

126 to 153

„ Kent Rag ....

166

„ Lias

127 to 156

Chalk . . . .

117 to 174

Quartz . . . . .

165

Felspar . . ...

162