In the park.
Sedimentary iron deposit.
Ref.: Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 998.
Bulletin de la Société française de Minéralogie (1982): 105, 321-326.