The American Geologist, Vol. XXVIII. 
Plate XXX. 
Fig 7 Lens in Rochester ravine, 150 yards north of east end of Seneca Park Bridge. Dimensions 14 x 40 
^feet. A— Rochester shale; B— upper bench ol Clinton npper limestone. 
Fig 8 Reef in I.ockport limestone, Niagara gorpe. one-half mile above Suspension bridge, by the^ 
Electric (Gorge) R. R. Length 110 feet; hight exposed, about 12 feet. 
REEF STRUCTURES. 
