APATITE (Ca,?)Ca4(PO4)3       Recently, micro apatite crystals were discovered in septaria at the Milan locality in Erie County and indicated as the first crystalline occurrence of the species in Ohio.   Similar crystals have also been sight identified from the Monroeville locality.  Furthermore, a greater variety and larger apatite crystals have been observed at the Monroeville locality than were reported from the Milan site.  The initial report described tabular apatite crystals, bound by a hexagonal prism and pinacoid, of unidentified species and less than 2 millimeters in size.  Two varieties were listed, white crystals with colorless rims or pale yellow crystals with brownish yellow centers.  Both of these forms have also been observed at the Monroeville locality where 4 distinct habits of apatite crystals up to 4 millimeters in size have been noted.  All of the apatite found at both of the  apatite with yellow and brown phantom crystal measures 1 mm  Huron River at Lamereaux road bridge Monroeville, Huron Co., Ohio white apatite with clear rim crystal measures 1.5 mm  Huron River at Lamereaux road bridge Monroeville, Huron Co., Ohio localities occurred between the 2nd and 3rd generations of ferroan dolomite and after the 2nd generation of quartz.  An example of a pale yellow to clear crystal with a bright yellow phantom outlined by a thin brown zone from the Monroeville locality is shown in the photo to the upper left.   The pinacoid faces of these crystals are often slightly convex to the point of eliminating the prism faces.   An example of a white crystal with clear edges also from the Monroeville locality is photographed to the lower left.  White crystals often have slightly dimpled or concave pinacoid faces and larger, more defined prisms.   Crystals that are entirely white with brownish black inclusions of pyrite as pictured to the upper right have been recovered at the Monroeville locality.  In addition, light yellow rosette-like crystals with brown edges have been found.  An example of this habit is displayed in the photo to the lower right.   All of the apatite crystals observed from this locality exhibit a distinctive white to sky blue fluorescence under short wave ultraviolet light.

white apatite crystals on 2nd generation ferroan dolomite (specimen Joseph W. Vasichko) largest crystal measures 3.5 mm West branch of the Huron River at Lamereaux road bridge Monroeville, Huron Co., Ohio yellowish tan apatite rosette with brown edges on quartz  (specimen Joseph W. Vasichko) crystal measures 2.5 mm West branch of the Huron River at Lamereaux road bridge Monroeville, Huron Co., Ohio

Galena on Ferroan Dolomite (specimen Joseph W. Vasichko) crystal measures 6 mm West branch of the Huron River at Lamereaux road bridge Monroeville, Huron Co., Ohio

GALENA PbS        A single specimen of galena was recovered from the Lamereaux road bridge locality.  While there is no prior report of galena at this locality, the occurrence is not entirely unexpected.   Galena, while rare in the state, is found as small crystals in concretions at various Pennsylvanian age locations.  Galena crystals are also periodically encountered in several Silurian age dolostone quarries near Toledo.  Several other occurrences of massive, non crystalline galena have also been reported across the state.  The specimen found at the Monroeville site has a single metallic gray, predominantly octahedral crystal with cubic modifications.  The faces of the crystal are smooth and slightly curved.  The crystal is partially damaged and shows a distinct cubic, mirror bright cleavage.  The crystal was found resting in the boxwork of 2nd generation ferroan dolomite on the back of a specimen with 3rd generation quartz crystals.  Unfortunately, this does not pinpoint the occurrence in the sequence.  In time, perhaps more galena specimens will be discovered and the mineral’s position in the sequence can be determined.  The photo to the left displays the galena specimen.  Although this particular galena specimen has little value, it does indicate the potential for better crystal specimens of a rarely seen Ohio species.

halotrichite-pickeringite on shale bank Although unidentified, this is more likely pickeringite. first shale cliff south of the cliff at Lamereaux road bridge West branch of the Huron River  Monroeville, Huron Co., Ohio

EFFLORESCENCES         Devonian age shales in Ohio are well known for producing thick masses of various efflorescences.  Two well known geographic landmarks which expose the Devonian shale were named for these accumulating efflorescences; Copperas Mountain in Ross County and Alum Creek in Delaware County.  At the Monroeville locality, thick masses of halotrichite-pickeringite, crusts of melanterite and masses and tiny crystals of gypsum as efflorescences are at times abundant on the under sides of shale ledges.   Efflorescences will not be described individually in this article, since these minerals are not found in septaria.  For reference, thick masses of white to yellow halotrichite- pickeringite are common after a long  period of hot dry weather.   Since the mineral series is water soluble and highly unstable, it disappears after heavy rain.  White crusts of melanterite can be found after a period of dry weather on the shale surrounding pyrite nodules.  Although efflorescences are quite interesting mineralogically, these minerals are too unstable and lacking in aesthetics to be of value to mineral collectors.  Specimens can only be preserved in air-tight containers.   During wetter periods, gypsum, which is more stable, is the more common efflorescence to be found at the locality.  Crusts, seams and tiny fibrous crystals of gypsum have been observed on shale, but are generally too small to be of interest to collectors. melanterite stain on pyrite and shale field of view is 20 cm x 25 cm West branch of the Huron River Monroeville, Huron Co., Ohio

Collecting Suggestions and Tips      While collecting along the Huron River can be very enjoyable, a great deal of effort is required to collect quality septarian minerals.  The casual collector may find this locality to be barren and frustrating as a large sledge hammer, splitting wedge, and pry bar are necessary to split open the large septaria and reach unexposed pockets.   The septaria at this locality have many ferroan dolomite and barite seams as well as other natural cracks which tend to be good splitting points.   A 2-4 lb. crack hammer and chisel are useful for trimming the broken pieces of the septaria.   The ferroan dolomite can be carefully chiseled away from the limestone matrix, occasionally in plates.   Most collectors will find that a rock hammer or rock pick are of little use at this locality, with the possible exception of digging through the shale to find pyrite nodules.   Other necessary items include safety glasses, gloves, buckets, newspaper, drinking water and bug spray.   A hand lens may also be useful.  Collectors will want to wear either boots or old shoes, but not sandals or other open toed shoes as the limestone fragments and shale can be very sharp.   Collectors should also expect to walk long stretches of the river to reach unbroken septaria, though fragments of septaria are found littered along the banks and occasional small specimens of fair quality can be collected from these.  Collectors should be prepared to carry both tools and specimens a fairly long distance.   A few collectors have attempted to use a gasoline powered concrete saw to slice into the septaria, though this is not necessary and in fact takes more effort than using traditional methods.   Like much rock collecting in the state, the easiest way to collect good specimens at this locality is to move a lot of rock.   A pair or more of collectors with a large sledge hammer and splitting wedge can move several times more rock than a single collector.   Random dead blow hits with a large sledge by a single collector are not nearly as productive as using a wedge, held by a second collector, to split apart the seams.   With the right tools, two diligent collectors can dissect multiple septaria in a single day if working together.   Furthermore, it is generally not a safe practice to collect alone, especially at a locality like the Huron River where there are numerous hazards.  When examining septaria, keep in mind that most pockets within will have only ferroan dolomite.  The large septaria often have very few pockets with large crystals of multiple minerals and these may be in one small area.   Additionally, some pockets in the septaria are filled with clay, which when washed out occasionally exposes good crystal specimens.

cliff exposing the late Devonian Huron shale West side of the West branch of the Huron River First shale cliff north of Lamereaux road bridge Photo 2004 Calcite on ferroan dolomite (specimen Joseph W. Vasichko) specimen measures 6.6 cm x 3.8 cm West branch, Huron River at Lamereaux road bridge Monroeville, Huron Co., Ohio

Visiting the Lamereaux road bridge locality      The Lamereaux road bridge locality and other sites along the west branch of the Huron River are among the most scenic places in Ohio to collect minerals.  The numerous shale cliffs rising up through the deciduous trees along the crystal clear river are very photogenic, especially in autumn.  The lucky visitor to the site may be treated to a fly over by the local nesting pair of American bald eagles.  Map of the Lamereaux road bridge locality The locality can be reached by taking Milan avenue  North from the center of Monroeville.  Milan avenue  becomes River road North of town. Visitors to the locality should park on the berm along Lamereaux road on the west side of the Huron River.  The river can be reached by several well traveled paths adjacent to the bridge.  Visitors should be mindful not to cross the fields and to remove all trash.  Failure to do so may result in the eventual closure of the site.  The best time to visit the locality is during dry periods throughout the summer when the water is low.   When the water is high, the locality should be avoided, as the river can be very dangerous.  The bed of the creek, which is composed of shale is often slick and the currents are very strong after significant rain.  Visitors should be aware that even during dry periods, there are very deep pools which should also be avoided.   Many of the high cliffs are severely frost cracked and all are very unstable and should never be climbed.

“Autumn Glory” scene along the West branch of the Huron River near the  Huron-Erie County line, north of the Lamereaux road bridge photo by  J. Astolfi

Summary      Septarian mineral specimens from the Huron River should be appreciated both for the aesthetic nature of the pieces and the uniqueness of the occurrence in Ohio mineralogy.  While these specimens are greatly unlike minerals from the better-known limestone and dolostone quarries in the state, and in some respects unlike those from other Devonian age septaria localities, the minerals from this locality should be accepted as being of equal importance and perhaps greater value.   Quality specimens from this location are more difficult to obtain than good pieces from many of the classic quarry localities where specimens are at times abundant.     The observations delineated in this article likely represent a very small portion of the mineral habits that this locality may potentially produce.   All of the mineral specimens photographed for this description were collected during a series of visits to the locality between the years 2000 and 2005.  The Lamereaux road bridge locality will undoubtedly produce additional mineral habits and associations in the future as individual septaria can be somewhat unique.  Additional mineral species may also be identified from septaria at this locality in years to come.  Indeed, several mineralogical aspects, both septarian and non septarian, of the locality deserve further study.   In particular, the origin and paragenesis of the various septarian minerals and how the sequence of mineralization at this locality is related to other similar occurrences throughout the Huron shale in Ohio.

slightly smoky quartz crystals on ferroan dolomite (specimen John D. Vasichko) specimen measures 7.4 cm x 6.4 cm West branch, Huron River at Lamereaux road bridge Monroeville, Huron Co., Ohio

 

This article in no way grants the reader permission to visit or collect along the West Branch of the Huron River at Lamereaux road bridge.   Permission must always be obtained before crossing or collecting on any private property.

 

References  Bingaman, Ann, Core, Doug and Boyer, Richard, 1978, Rock and Mineral            Collecting sites in Ohio, Ohio Historical Society Natural History            Information Series, v. 5 no. 3 Broadhead, R.F., Kepferle, R.C. and Potter, P.E., 1980, Lithologic            descriptions of cores and exposures of Devonian shale and associated            strata in Ohio along Lake Erie: U.S. Geological Survey Open-File            Report 80-719 Carlson E.H., 1977, Mineralogy of the septarian concretions from Ohio            (abstract): Tuscon Arizona, Third Mineralogical Society of America-            Friends of Mineralogy Symposium Carlson E.H., 1991, Minerals of Ohio: Ohio Division of Geological Survey  Carlson E.H., 2002, "Ohio Mineral locality Index, part 2: Concretions and            Miscellaneous occurrences", Rocks and Minerals v. 77  Case Western Reserve University (CWRU) Department of Geological            Sciences, The Jesse Earl Hyde Collection, slide 1006 Dana, E.S. and Ford, W.E., 1932, A textbook of Mineralogy( 4th ed.):New            York, John Wiley and Sons Hyde, C., and Landy, R.A., 1966, “Whewellite from Septarian Concretions            near Milan, Ohio”, American Mineralogist v. 51  Newberry, J.S. 1874, Report on the geology of Erie County and the Islands;            Lorain County: Ohio Division of Geological Survey, v. 2, pt 1 Prosser, C.S., 1913, The Huron and Cleveland Shales of Northeastern Ohio,            Ohio Division of Geological Survey Bulletin 15 R.P. Richards and J. Rakovan, 2000, “Contributed Papers in Specimen            Mineralogy Part 2; 26th Rochester Mineralogical Symposium -The            First Occurrence of Apatite in Ohio”, Rocks and Minerals v. 75 Sinkankas, John, 1964, Mineralogy for Amateurs; Van Nostrand Company            Inc. Williams, W.W. 1879, The History of the Firelands, Comprising Huron and            Erie Counties, Ohio: Cleveland, Ohio: Press of Leader Printing            Company.

Calcite crystals on ferroan dolomite (specimen Joseph W. Vasichko) largest calcite crystal measures 1.2 cm West branch, Huron River at Lamereaux road bridge Monroeville, Huron Co., Ohio