...beds, which, underlying the Tertiary in Virginia, and the well marked Cretaceous formation further north, have, in the latter region, been regarded as...formation consists typically of a rather coarse, and somewhat .pebbly sandstone, in which the grains of quartz and felspar are feebly cemented by kaolin,...

...not with any more definiteuess. lie says,3 in speaking of the Potomac beds: These are the siliceous, argillaceous, and pebbly beds which, underlying the...decomposition of the latter, and of argillaceous and siliceous clays, variously colored and more or less charged with vegetable remains, either silicificd...

...pebbly beds, which, underlying the tertiary in Virginia, and the wellmarked cretaceous formation further north, have, in the latter region, been regarded as...pebbly sandstone, in which the grains of quartz and felspar are feebly cemented by kaolin, derived from the decomposition of the latter, and of argillaceous...

...pebbly beds, which, underlying the tertiary in Virginia, and the wellmarked eretaceous formation further north, have, in the latter region, been regarded as belonging to the base of the eretaceous series of the Atlantic States. In Virginia the formation consists typically of a rather...

...not with any more definitencss. lie says,3 in speaking of the Potomac beds: These are the siliceous, argillaceous, and pebbly beds which, underlying the...decomposition of the latter, and of argillaceous and siliceous clays, variously colored and more or less charged with vegetable remains, either silicified...

...not with any more deflniteuess. He says,-1 in speaking of the Potomac beds: These are the siliceous, argillaceous, and pebbly beds which, underlying the...regarded as belonging to the base of the Cretaceous scries of the Atlantic States. In Virginia the formation consists typically of a rather coarse and...

...beds, which, underlying the tertiary in Virginia, and the well marked cretaceous formation further north, have, in the latter region, been regarded as...pebbly sandstone, in which the grains of quartz and felspar are feebly cemented by kaolin, derived from the decomposition of the latter, and of argillaceous...