The Eramosa is a Silurian stratigraphic unit exposed along the Niagara Escarpment in Ontario and western New York State. In the late nineteenth century it was an important source of building stone in Hamilton and Waterdown, in the late twentieth century quarries in a similar unit called the Eramosa, near Wiarton in the Bruce Peninsula, became an important source of dimension stone at a time when most of the other resources of similar stone were depleted. Work in these quarries led to the discovery of exceptionally well preserved fossils. On the east Mountain at Hamilton, a well-developed cave system was discovered in the Eramosa and has now been designated as the Eramosa Karst Conservation Area; the term was first used for a stratigraphic unit by Williams who named the Eramosa Member for the bituminous dolomites exposed below the Guelph Formation along the Eramosa River, northeast of Guelph, Ontario. No detailed description of the type section has been published, the status of the unit has been subject to many different interpretations.

Until the Eramosa in Ontario was regarded as the highest Member of the Lockport Formation, with gradational contacts with the Goat Island Member and the Guelph Formation. In 1995, the US Geological Survey proposed a revised stratigraphy based on studies in the Niagara region, it extended the Lockport to Group status and included, from base to top, the Gasport, Goat Island and Guelph as Formations within the Lockport Group. In a "reference section" in the Niagara River Gorge, the Eramosa was divided into six "units" recognized throughout the Niagara region, but a shaley lower unit named for the Hamilton area was transferred to the Goat Island Formation. Brunton has proposed a revision for Ontario which restores the Vinemount Member to the Eramosa and recognizes two other members; the exact age and correlation of the Eramosa are still uncertain. Conodonts at first indicated that the Eramosa age was Ludlovian, but recent studies of both conodonts and the Eramosa lagerstätte suggest an earlier, late Wenlockian age.

The rocks forming the Eramosa are dolomites, but the composition varies from pure, grey-weathering, fine grained dolomite to shaley, brown-weathering, bioturbated dolomites. Fossils are common at some localities, scarce at others, chert is a minor component; the most characteristic feature is bituminous shaley interbeds. The Eramosa was deposited in several related environments, most including shallow, restricted marine waters. Among the fossils the most spectacular are the eurypterids, an extinct form of scorpions; some species lived in fresh or brackish water. The exceptionally preserved biota are present in a stratum of rock about 8 m thick, which extends for around 16 km in the South Bruce Peninsula, Ontario. Bancroft, A. M. M. A. Kleffner and F. R. Brunton. Silurian conodont biostratigraphy and δ13 C stratigraphy of the Eramosa Formation, southwestern Ontario, Canada. Geological Society of America Abstracts with Programs, v.40 p. 22. Brett, C. E. et al.. Revised Stratigraphy and Correlations of the Niagaran Provincial Series in the Type Area of Western New York.

U. S. Geological Survey Bulletin 2086, 66 p. Brunton, F. R.. Update of revisions to Early Silurian stratigraphy of the Niagara Escarpment: Integration of sequence stratigraphy and hydrogeology to delineate hydrogeologic units. Ontario Geological Survey Open File Report 6240, p. 25-1 to 25-20. Collette, J. H. and D. M. Rudkin. Phyllocarid crustaceans from the Silurian Eramosa Lagerstätte: Taxonomy and functional morphology. Journal of Paleontology, v.58 p. 116-127. Johnson, M. D. et al.. Phanerozoic Geology of Ontario. 1, p. 907-1008. Von Bitter, P. H et al.. Eramosa Lagerstätte – Exceptionally preserved soft-bodied biotas with shallow-marine shelly and bioturbating organisms. Geology, v.35 p. 879-883. Williams, M. Y.. A eurypterid horizon in the Niagara Formation of Ontario. Geological Survey of Canada Museum Bulletin 20, 21 p. List of types of limestone

Jennifer F. Reinganum

Jennifer F. Reinganum is an American economist, she lives in Nashville, Tennessee where she is the E. Bronson Ingram Professor of Economics at Vanderbilt University, she has been a professor of economics since 1995. Reinganum was the president of the American Law and Economics Association for 2012 and has received multiple grant awards from the National Science Foundation. Jennifer F. Reinganum received two bachelor's degrees, one in Mathematics and one in Economics, from Oberlin College in 1976, she continued her education at Northwestern University where she received her master's degree in Quantitative Methods in 1978. Reinganum stayed at Northwestern and received her Ph. D. in Managerial Economics and Decision Sciences in 1979