The Petrology Review

 

How the review works

The aim of the review is to establish material that is of scientific merit and specimens, which are good representatives, possessing public potential for display and community events. These two criteria do not necessarily go hand in hand; as a specimen may have a fantastic scientific research potential, but may not be visually impressive. Therefore the specimens are graded against two separate criteria: Scientific Merit (as a numerical value of stars) and Public Engagement (as a Gold, Silver or Bronze status).

For a more in depth look into the review criteria, click on the “Review Criteria” tab in the tool bar above.

 

 

 The Petrology review

Petrology is sub-divided into three main groups: Igneous, Metamorphic and Sedimentary.

The Sedimentary petrology collection is the largest of the three groups, and consists of 74 trays containing 1,132 specimens. The amount of material created a huge dilemma as to which method would suit the review. It was decided to be conducted as a rapid, systematic, tray by tray investigation, rather than an initial overview of the entire collection; followed by an in depth look at a compiled shortlist.

A summary of reviewed material

Limestones & Dolomites, Chalks, Sandstones, Siltstones, Mudstones, Shales, Conglomerates, Hydrocarbons & Organics*, Extraterrestrial rocks, and Features**.

Sian with a few trays.

 

* “Organics” refers to material of an organic nature, this differs to palaeobotany, and features: Amber, Copalite, Jet, Bitumen, Coal and Elaterite.

** “Features” refers to sedimentary rocks which exhibit unusual structures: wave or ripple preservation, Cone-in-cone and Septarian nodules.

 

Day One.

Dr Sian Davies-Vollum led the review with some wonderful and curious specimens being discovered and highlighted some historically important UK material.

Leedm.B.1998.03.0608

Notably the striking landscape marble or Cotham marble (1 Gold star – Leedm.B.1998.03.0608) from Bristol, a highly calcareous stromatolitic limestone and is prized for it’s “landscape” or hedgerow patterns.

Leedm.B.1993.03.0029

Also, Shale with beef (2 Silver stars – Leedm.B.1993.030029) from Charmouth in Dorset, a very distinct shale with a fibrous calcite structure, noted as a Lower Jurassic marker bed.

Leedm.B.TN2965

 

Plus the figured specimen of Rhaetic bone bed (2 Silver stars – Leedm.B.TN2965) from Aust Cliff in Gloucestershire, which exhibits no fossil material but contains numerous fine tapering lenses.

 

In addition, three wonderful and unusual specimens of Magnesian limestone concretions (1 Silver star – Leedm.B.1980.06.0096.1-3) found near Durham.

Leedm.B.1980.06.0096.1-3

The final tray of limestones.

 

The first day of the review managed to cover limestones, dolomites, chalks, shales and mudstones; featuring some striking banded mudstones (not pictured). A lot of material was reviewed, with limited highlights.

 

 

 

Day Two.

The second day of the review commenced with sandstones, and managed to cover conglomerates, siltstones, features, organics and extraterrestrial rocks. These yielded a far greater number of notable specimens, with some surprising discoveries.

Flexible sandstone

One of the highlights was a number of very strange and amazing Itacolumite or Flexible sandstone specimens from India. Click here to witness the flexibility. Also some uncommon but wonderful specimens of Imatra stones (2 Bronze stars – Leedm.B.TN411) from Scotland, odd little concretions often referred to as “Fairy Stones”.

Leedm.B.TN411

Leedm.B.2011.34

 

The ultimate highlight for Sian was a very unusual and rare specimen of Desiccation cracks     (2 Gold stars – Leedm.B.2011.34), as a discontinuous band of pink mud flakes with an unusual lower surface of rip-up clasts.

Leedm.B.2009.076

Another wonderful specimen is a small and often easily overlooked sample of Fulgurite (1 Gold star -Leedm.B.2009.076). A small tube of fuse quartz formed as the result of a lightning striking.

There was also an interesting Jurassic Laminated sandstone (1 Silver star – Leedm.B.2010.50) from Cayton bay in Yorkshire, featuring vertical burrow structures and carbonaceous root deposits with mica flecks.

Leedm.B.2010.50

 

The collection contains numerous Septarian nodules, these are very common, but two noteworthy specimens are (0 Bronze stars – Leedm.B.TN5412); an interesting complete nodule with crack infill in relief, as a result of weathering. The other is (0 Bronze stars – Leedm.B.2011.33), a split nodule in cross section, illustrating the extensity of cracking throughout the calcite cemented nodule.

Leedm.B.TN5412

Leedm.B.2011.33

 

 

 

 

 

 

 

 

Leedm.B.TN1803

 

Leedm.B.1980.06.0062.1-2

Another highlight was a very unusual specimen of Conglomerate (0 Silver stars – Leedm.B.TN1803), featuring numerous small rounded clasts coated in a green film.

 

Along with another wonderfully named conglomerate; Pudding stone (0 Bronze stars – Leedm.B.1980.06.0062.1-2), consisting of rounded agate clasts in a very fine grained matrix. The specimen has been cut and polished to emphasise its structure.

 

 

The Hydrocarbons and organics revealed some striking specimens of Jet and Bituminous Coal with amazing lustres, plus some stunning samples of resin Copalites with organic inclusions.

Leedm.B.1955.61.0229

A particular highlight is this specimen of Amber (1 Silver star – Leedm.B.1955.61.0229) from the Baltic Coast, with some obscured but strange unidentified inclusions.

Leedm.B.TN5396

 

The collection also contains a number of somewhat peculiar specimens know as Cone-in-cone           (1 Silver star – Leedm.B.TN5396), these are sedimentary features as a series of concentric cones nested inside each other.

 

 

Lastly, the extraterrestrial material comprises of four Pallasite Meteorites from various locations around the world. Two of the specimens are whole and two occur as cut cross-sections, revealing the striking interior of iron with olivine infill voids (3 Gold stars – Leedm.B.1985.05.01) from the Haviland Crater in Kansas, USA.

Leedm.B.1985.05.01

Looking at the larger specimens.

 

The review covered 1,132 specimens, establishing the following summary.

Gold = A truly amazing specimen; Silver = A very good specimen that has great potential; Bronze = A good specimen which can demonstrate a particular feature; Clear = A specimen that has limited visual qualities.

3 stars = High scientific importance; 2 stars = Moderate scientific importance; 1 star = Fair scientific importance; 0 stars = Supported by limited or no documentation.

 

Summary of the Sedimentary petrology collection.

 

Strengths

1) There are good suites of sedimentary rocks collected from the region. This is particularly true for rocks originating from the Carboniferous Coal Measures. They could be used to ‘tell a story’ about the rock sequences in which coal is found and the significance of these in the region.

2) There is a good breadth of sedimentary rock types in the collection with most key rock types included. This range of rocks can be used as a basis for teaching sedimentary petrology and interpretations of sedimentary rocks.

3) There are a number of unusual sedimentary rocks represented by multiple hand specimens e.g. Itacolumite (flexible sandstone from India) and ‘landscape marble’ (Cotham marble, a stromatolitic limestone).

Weaknesses

1) There are many unusual and/or interesting samples that lack information about where they were collected. This lack of information makes it difficult for any researcher to place these samples into stratigraphical or geographical context.

2) Some of the samples are in need of cleaning and preparing to reveal details of their petrology.

3) Apart from a collection made from central Europe, most specimens come from the UK.

 

I would like to say a heartfelt “thank you” to Sian for reviewing this volume of material, and bringing to light such an interesting and often overlooked series of rocks over the two intense, but fun days.

 

The sedimentary petrology, along with all the other collections are open and free for anyone to view by appointment, just call Leeds Discovery Centre on 0113 378 2100 or email discovery.centre@leeds.gov.uk

The Crinoid Review

How the review works

The aim of the review is to establish material that is of scientific merit and specimens which are good representatives, possessing public potential for display and community events. These two criteria do not necessarily go hand in hand; as a specimen may have a fantastic scientific research potential, but may not be visually impressive. Therefore the specimens are graded against two separate criteria: Scientific Merit (as a numerical value of stars) and Public Engagement (as a Gold, Silver or Bronze status).

For a more in depth look into the review criteria, click on the “Review Criteria” tab in the tool bar above.

 

The Crinoid review

Fiona referencing a crinoidal slab.

 

The Crinoid collection consists of 13 trays. It was decided that the amount of material would suit the review being conducted as a detailed, systematic, tray by tray investigation, rather than an initial overview of the entire collection, followed by an in depth look at a compiled shortlist.

 

 

Day One.

Dr Fiona Fearnhead led the review with some very obvious and truly spectacular specimens jumping out from the start.

Leedm.B.2009.065.1

The scientific highlight is the historically important holotype of Platycrinites selwoodensis (2 Gold stars – Leedm.B.2009.065.1) and a Dialutocrinus triacondylactilus (1 Gold star – Leedm.B.2009.065.2) both specimens are from Frome in Somerset, UK.

Leedm.B.2009.065.2

Fiona taking a quick picture of a star specimen.

 

In addition to these specimens, the collection contains some important Ludlow and Wren’s Nest UK SSSI material, with some specimens from historically important collectors; notably associations with Etheldred Benett and the Leeds collector Benjamin Holgate.

 

 

 

The systematic review highlighted a lot of material as having wonderful potential for public engagement with limited scientific merit, notably a Pentacrinus fossilis  (0 Gold stars – Leedm.B.2010.127) exhibiting beautifully preserved brachials, pinnules and cirris.

Leedm.B.2010.127

In addition, a Periechocrinties mammiliformis  (1 Gold star – Leedm.B.1990.01.4076) exhibiting three calcified zenomorphic stems, illustrating the columnal transition from base to cup. There is also a good example of a Platycrinites sp. (1 Bronze star – Leedm.B.TN5184) being a mass of crinoidal columnars and ossicles on a limestone matrix.

Leedm.B.1990.01.4076

Leedm.B.TN5184

 

 

 

 

 

 

 

Some interesting material with research potential was discovered, specimens of note are Periechorinus sp. (2 Gold stars – Leedm.B.TN4694) from the Wren’s Nest SSSI site, exhibiting a fine calyx structure and articulated brachials.

Leedm.B.TN4694

 

 

 

 

 

 

Leedm.B.TN1154

 

 

 

 

Along with a Periechocrinus moliliformis                     (1 Silver star – Leedm.B.TN1154), featuring crinoidal material on both surfaces of the Wenlock limestone.

 

Day Two.

The review resumed with some amazing and somewhat surprising discoveries, notably an uncommon holdfast from a Woodocrinus sp. (2 Silver stars – Leedm.B.TN5536), these are often overlook when collecting, and can be a rarity in museum collections. There was also the discovery of numerous Apiocrinus sp. ossicles and complete calyces from the Jurassic, Bradford clay. One of note is the Apiocrinus parkinsoni (0 Bronze stars – Leedm.B.TN1160).

Leedm.B.TN5536

Leedm.B.TN1160

Leedm.B.TN168

 

 

Three other unidentified crinoids specimens of note are: a mass of crinoidal material on a limestone matrix (0 Silver stars – Leedm.B.TN168); a fine plated calyx with articulated delicate brachials and pinnules (2 Silver stars – Leedm.B.TN1148); and a wonderful example, exhibiting fine anatomical details of a proximal columnar (1 Silver star – Leedm.B.TN1161).

Leedm.B.TN1148

Leedm.B.TN1161

 

 

 

 

 

 

 

 

 

Two specimens worthy of a mention but not photographed here are: (1 Clear star – Leedm.B.TN1347) an unidentified crinoid that exhibits a physical response to environmental or parasitic stresses; and a wonderful specimen of Periechocrinites  moniliformis (3 Gold stars – Leedm.B.2008.00.006) from the Wren’s Nest SSSI, which is on display in the Life on Earth Gallery at Leeds City Museum.

 

The review was finally capped off with Fiona enlightening me to the absolutely incredible footage of a crawling extant crinoid… Amazing!

http://palaeo-electronica.org/2007_1/crinoid/fig3.htm

 

The review covered 178 crinoid specimens, establishing the following summary.

 

Gold = A truly amazing specimen; Silver = A very good specimen that has great potential; Bronze = A good specimen which can demonstrate a particular feature; Clear = A specimen that has limited visual qualities.

3 stars = High scientific importance. 2 stars = Moderate scientific importance. 1 star = Fair scientific importance. 0 stars = Limited or no scientific importance.

 

Summary of the Crinoid collection.

Strengths

The collection contains some research possibilities, and has broad examples from a periodic breadth, with many facets of columnals that could warrant future research into stems, with the Silurian material being from key localities of historical significance. There are numerous Apinocrinites specimens which can illustrate calyx and stem articulation within the group, using individual sections, ossicles and cross sections. The abundance of Carboniferous material can easily illustrate size changes and morphology adaptations.

 

Weaknesses

Sadly the loss of data on some prime specimens diminishes research value, and the unfortunate pyrite decay of a large Lyme Regis specimen.

 

To close, I would like to say a huge “thank you” to Fiona for reviewing this material and the laughs along the way.

 

The Crinoids, along with all the other collections are open and free for anyone to view by appointment, just call Leeds Discovery Centre on 0113 378 2100 or email discovery.centre@leeds.gov.uk

The Arthropod Review

How the review works

The aim of the review is to establish material that is of scientific merit and specimens which are good aesthetic representatives, possessing public potential for display and community events. These two criteria do not necessarily go hand in hand; as a specimen may have a fantastic scientific research potential, but may not be visually impressive. Therefore the specimens are graded against two separate criteria: Scientific Merit (as a numerical value of stars) and Public Engagement (as a Gold, Silver or Bronze status).

For a more in depth look into the review criteria, click on the “Review Criteria” tab in the tool bar above.

 

The Trilobite review

Joe investigating a trilobite tray

 

The Arthropod collection consists of 14 trays made up of 9 Trilobites and 5 other Arthropoda (fossil Crustaceans, Insects and a Sea Scorpion cast). It was decided that the amount of material would suit the review being conducted as a detailed, systematic, tray by tray investigation, rather than an initial overview of the entire collection, followed by an in depth look at a compiled shortlist.

 

Day One.

Leedm.B.TN5840

Dr Joseph Botting led the review, which resulted in some specimens making an impact at the outset. The collection contains some important SSSI material from the Burgess Shale and Wenlock limestone     (2 Gold stars – Leedm.B.TN5840).

 

Leedm.B.1876.5.2

The scientific highlights are the historically important Bohemian specimens, donated to the museum in 1876 by Dr Antonin Frič, the director of the National Museum Prague. One of these specimens, Miraspis mira      (2 Silver stars – Leedm.B.1876.5.2) is quite rare, with distinct spines on the pygidium. The function of these spines is uncertain; but Joe suggested they are likely to be a camouflage feature rather than a defensive structure.

 

Leedm.B.TN4896

As the review progressed it became apparent that some material has wonderful potential for public engagement. Notably a common specimen Encrinurus punctatus  (0 Silver stars – Leedm.B.TN4896), exhibiting interesting lumps on the glabella, which maybe a function of camouflage.

 

Unfortunately much of this material has little scientific merit, with two wonderful but very common Dalmanites myops specimens (0 Silver stars – Leedm.B.TN4907) and (0 Gold stars – Leedm.B.TN4899); both are fine examples of schizochroal – compound eyes structures.  

Leedm.B.TN4907

Leedm.B.TN4899

 

Some rarer and slightly trickier to find material was discovered in the form of Peronopsis interstricta (2 Gold stars – Leedm.B.TN2015), a planktonic filter feeder from Utah.

Leedm.B.TN2015

Joe with his trusty hand lens.

 

 

 

 

 

 

 

 

 

 

Day Two.

The review resumed and revealed some surprising discoveries, notably a Calymene blumenbachi specimen with damaged ribs       (2 Gold stars – Leedm.B.TN5586).

 

Leedm.B.TN5586

On closer inspection it was interpreted as predatory damage from a Sea Scorpion’s pincer. The specimen is the actual trilobite and not a moult, which therefore implies that the trilobite must have survived the initial attack but died within one moult cycle.

Two other Silurian specimens of note are a wonderful example of a Bumastus barriensis (1 Bronze star – Leedm.B.2010.72) an infaunal ambush predator, and another lovely example of Calymene blumenbachi (1 Silver star – Leedm.B.TN5836) exhibiting granular ornamentation on the cephalon.

Leedm.B.2010.72

Leedm.B.TN5836

 

 

 

 

 

 

 

 

 

 

The review covered 204 trilobite specimens, establishing the following summary.

Gold = A truly amazing specimen; Silver = A very good specimen that has great potential; Bronze = A good specimen which can demonstrate a particular feature; Clear = A specimen that has limited visual impact.

Joe referencing a tricky specimen.

3 stars = High scientific importance.

2 stars = Moderate scientific importance.

1 star = Fair scientific importance.

0 stars = No or limited scientific importance.

 

With the Trilobite review completed, Joe kindly suggested to review the remaining arthropods; with some wonderful results that would have gone undiscovered.

 

 

Review of additional Arthropod material

The highlights of this additional review include a wonderful horseshoe crab Mesolimulus walchi (2 Gold stars – Leedm.B.2010.186) from the Solnhofen limestone.

Leedm.B.2010.186

Leedm.B.2003.01.01

 

 

An additional specimen of Bellinurus trilobitoides (1 Silver star – Leedm.B.2003.01.01) found locally in Leeds.

 

 

Leedm.B.TN4865

 

Similar to the trilobites, the bulk of the collection is of a limited scientific merit, but contains some wonderful material for public engagement, notably a Hoploparia sp.  (1 Silver star – Leedm.B.TN4865).

 

In addition, a wonderful beetle specimen, Cybister explanatus from the La Brea Tar Pits. And last but not least, an interesting and scientifically important bedding plane of crustaceans; exhibiting exceptional soft body preservation from a potential and undescribed Silurian lagerstätten in the UK, both not photographed here.

 

The additional review of arthropod material covered 85 specimens, establishing the following summary.

 

Summary of the Trilobite collection.

The collection contains wide ranging material with a lot of fine specimens, but unfortunately lack scientific importance. The collection has not been acquired systematically with donors providing unusual material, with no focus on trilobite sourcing. There is a number of research grade Carboniferous material, featuring a wide range of named species from Malham Tarn and Doncaster.

 

Strengths

Strong representations of the following groups:

Phacopida group – illustrating eye morphology, life habits and enrolment.

Asaphida group – exhibiting microevolution with species level taxonomy of Trinuclid evolution.

Proetida group – as a conservative group.

Specimens occur as moults and/or complete specimens with compressional and three-dimensional preservation.

The Bohemian material extends the fauna of the collection and adds an impressive element, making these the highlight of the collection along with other non UK specimens from France, Morocco and Utah.

 

Weaknesses

There are limited specimens from the Lichida, Agnostida and Harpetida groups and no examples from the Eodiscida and Raphophoridae groups.

The Proetida are local Carboniferous, and there are very few specimens from the Scottish side of the Iapetus.

 

Finally, I would like to thank Joe for this review and all he’s done. It was great fun and a wonderful two days.

The Arthropods, along with all the other collections are open and free for anyone to view by appointment, just call Leeds Discovery Centre on 0113 378 2100 or email discovery.centre@leeds.gov.uk