55 
square showing cross ripple-marks, large glaciated surfaces from 
the well-known Kelly’s Island (Ohio) locality, and others. 
Upon the wall are framed specimens of the so-called ruin 
marble, a rock in which the natural faulting and coloring has been 
such as to give to the slab an appearance like a painting of a 
ruined city. 
Pedestal G. — Surface of sandstone, three by four feet, show- 
ing ripple-marks, from Berea, Ohio. 
Pedestal 7. Collection of basaltic columns from the Giant’s 
Causeway, Ireland, and the Rhine Valley. The grouping of these 
is intended to illustrate the stair-like arrangement which usually 
characterizes cliffs of basalt. The columns are of entirely natural 
formation, being produced by the shrinkage of the basalts from 
cooling. 
Other illustrations of types of structure not exhibited here 
will be found in Hall 66. 
