Graph of Relative Reef Sizes from North to South
Silurian reefs of the Racine Formation show a general increase in size from north to south. At Grafton, reefs have maximum breadths of about 60 m. In the Milwaukee area, reefs have breadths of 100 to 300 m, and further south, the reef at Thornton is about 2000 m in breadth. Maximum thickness of reefs across this area increases from 5 to 90 m.
