Blackberry Hill

The strata at Blackberry Hill are known to belong to the Elk Mound Group; however, the lack of good stratigraphic markers (i.e., index fossils) in some Blackberry Hill localities, coupled with uncertainties about the age range of the Elk Mound Group itself, make it difficult to assign a precise age to these strata. Many researchers consider these rocks to be Late Cambrian, which is the age to which the Elk Mound Group was originally assigned; however, some recent authors now believe the Elk Mound Group and the fossils of Blackberry Hill could date back to the Middle Cambrian, based on certain fossils obtained from other areas. == Geological and environmental setting ==

Most of the strata are composed of well bedded quartz sandstone and orthoquartzite. They were deposited mainly on intertidal and supratidal zones of tidal flats of an inland sea of the supercontinent Laurentia. Ripple marks and numerous other sedimentary structures identical to those found on modern beaches abound on the strata surfaces. One of the most conspicuous features is extensive areas of specific structures not unlike those associated with modern biofilms and microbial mats. It is also believed that the same material aided in the exceptional preservation of many of Blackberry Hill's trace fossils. == Significance==

Among the many paleontological discoveries thus far made at Blackberry Hill are the following: • The first body fossils, and therefore the identity, of one of the first animals to walk on land. • What may be the first mating behavior in the fossil record. The largest, most productive quarry is still in operation, thereby revealing fresh surfaces and the potential for new discoveries on a continuing basis. == Biota ==

Sedimentary structures associated with biofilms and microbial mats Being composed mainly of water, scyphozoans rarely fossilize; however, they are found by the hundreds on some surfaces of one Blackberry Hill quarry. The size of these fossils is also noteworthy; some specimens have achieved a diameter of 95 cm, making them the largest scyphozoan fossils on record. == Trace fossils ==

• Protichnites – These trackways (up to 8 cm wide at Blackberry Hill) are characterized by two parallel rows of paired footprints, often in sets, and a medial furrow or series of medial impressions, presumably from a dragging or touching tail. The maker of Protichnites was conjectural since 1852, when Sir Richard Owen, the pioneering British anatomist and paleontologist who coined the term “dinosauria,” first named and described them based on material from equivalent strata of Quebec. Fossils from Blackberry Hill named P. eremita, found over 150 years later, solved the mystery by eventually revealing that at least some Protichnites were likely produced by the euthycarcinoid Mosineia macnaughtoni. In these cases, the top layer might then exhibit Protichnites due to the tail that dragged on the surface, and the bottom layer would result in the furrow-less Diplichnites. It is possible that some Diplichnites were produced by trilobites or unknown arthropods, but no fossils of trilobites have been found thus far at Blackberry Hill. • Climactichnites – These distinctive trace fossils, up to 14 cm in width and resembling tire tracks, are the most conspicuous trails at Blackberry Hill, literally covering large surfaces of certain strata. Two ichnospecies are found: C. wilsoni, which are surface trails that have lateral ridges; and C. youngi, which are burrows that lack lateral ridges. Occasionally the resting trace, Musculopodus, is found at one end of a C. wilsoni. ==References==