Science. N. S. Vol. Ill, Plate 1. 



Illustrations to Article by G. K. Gilbert on Hypotheses. 



Fig. 1. — Loiiar Lake, India, oc-oiipyiiig au explosion 

 crater. From Newbold's Suiiiiimi!/ af the OeoJor/i/ of 

 Siiutlieni India, Jour. Koy. .\siatic Soc, vol. 9, p. 

 40. London, 1848. 



Fig. 2. — The limestone crater of Arizona, Coon 

 Butte, as seen from the south. Photograph of a 

 model hy Mr. Victor Mindeleff. 



Fig. 3. — Contour map of Coon Butte. The vertical 

 distance from contour to contour is ten feet. Lines 

 of drainage are dotted. 



Fig. 4. — Restoration of the site of Coon Butte before 

 the formation of the crater. Contour interval, ten 

 feet ; lines of drainage dotted. Compare ivith 

 Fig. 3. 



Fig. ft. — Volcanic I indii-ci>nc- -witli (later, north of 

 San Francisco Mountain, Arizona. The position of 

 the crater, at top of the hill, is characteristic of 

 most volcanoes. Compare Fig, 2, where the crater 

 lies chieflj' below the level of the plain. 



Fig. (i. — Craters iiiadi' by throwing clay ballsat a clay 

 target. A ball of the same size is shown. 1 shows 

 the effect of high velocity, 2 of low. 



