Finally , he joined Tufts College in 1892 , becoming the Pearson professor of geology and mineralogy .
He became assistant state geologist for Michigan in 1892 , and from 1899 to 1909 he was the state geologist .
State geologist joined Tufts College in 1892 , becoming the Pearson professor of geology and mineralogy .
He became assistant state geologist for Michigan in 1892 , and from 1899 to 1909 he was the state geologist .