Plate XXVII. 
Fig. 1. — View of the recent excavation west of the track at Avon, Iowa, look- 
ing northeast across the valley of the Des Moines river. The water in 
the excavation is said to be eighteen feet deep. A test boring is reported 
to have revealed continuous sand and gravel to a depth of thirty feet 
below the surface of the terrace. 
Fig. 2. — View of a portion of the old excavation east of the track at Avon, 
loy/a. Here the water is but three to four feet deep. The stratification 
of the sand and gravel is very evident in the foreground. 
