Investigating the rocks of Saint Croix National Scenic Riverway (SACN) is a tougher nut than working in MNRRA. Most of the area where rocks are exposed in MNRRA is part of some kind of park (city, state, regional, county, etc.) and generally accessible to the public. Much of the area with outcrops on the St. Croix is private land, and many of the key localities in the literature are now overgrown, destroyed by construction, or are roadcuts next to busy highways. Determining where you are in the strat column is also more difficult. In MNRRA, it's hard to get mixed up if you can tell sandstone from limestone/dolomite and shale. In SACN, you're dealing with several quartz-rich medium to coarse sandstones that tend to look the same, with some intervening shaly, dolomitic, or finer-grained sandy formations, and in the literature practically every single investigator had their own preferred system of names right up until the 1960s. Finally, in MNRRA there are abundant and diverse fossils in the Platteville and Decorah, while in SACN the special of the day is the BLT (burrows, lophophorates [brachiopods and hyoliths], and trilobites) with a side order of mystery snails, and you have to work for everything but the B.
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| The sweet siren song of the Franconian trilobite. |