LJ R. Lucas Jackson Fossil Preparation & Geoscience
Prep portfolio

Preparation record

Nine specimens, each shown as it arrived, partway through, and finished. Where there are photographs from more than one sitting you can step through them. Click any photograph to enlarge it.

01

Miocene Equid Thoracic Vertebra (field no. 399)

Prepared at Ashfall Fossil Beds for the University of Nebraska State Museum. A plaster field jacket came in from the ash bed, was opened on the bench, and the vertebra inside was worked free of the volcanic ash it had been buried in. The fragments that came out alongside it were kept with the specimen. Four days from closed jacket to a cataloged element in a box.

Closed plaster field jacket with its field number painted on the outside, resting on a lab bench beside a specimen worksheet
The jacket as it reached the lab, field number painted on the plaster.
Both halves of the opened plaster jacket set side by side outdoors on a boardwalk rail
Both halves off, with the ash the bone was packed in still in place.
Half of the plaster jacket on the bench with volcanic ash matrix picked away into a pile, a dental pick and brush alongside
Ash worked back with a pick and a brush.
A hand holding the bone clear of the ash, with a wooden dowel, toothbrush, spoon and brush laid out on the bench
Bone clear of the ash, with the tools that got it there.
The vertebra standing upright in a tray of sand, its pieces held in contact
Pieces held in contact, standing in a tray of sand.
The finished vertebra photographed with the centrum face toward the camera and the neural spine running away below it
Centrum face toward the camera, neural spine running below.
The finished vertebra beside its handwritten University of Nebraska State Museum label, with the fragments that came out of the jacket boxed alongside
Boxed with its museum label and the fragments that came out with it.
Museum
University of Nebraska State Museum
Field no.
399
Age
Clarendonian
Taxon
Equid
Desc.
Thoracic vert
Formation
Ash Hollow
Locality
AP116
Isolated element in ash bed

Transcribed from the specimen label in the last photograph.

02

Green River Fish Plate, Quarry to Finished

Split, collected and prepared at a Green River Formation quarry for In-Stone Fossils. The fish turned up on a freshly split layer in the quarry floor. It came off the hill in two pieces, was rejoined and cleaned on the bench, and finished as a single plate. A rock hammer sits beside it in the first photograph for scale.

A deep-bodied fossil fish lying exposed on a freshly split limestone layer in the quarry floor, with a rock hammer beside it for scale In the quarry
The same fish on a workshop bench, the two halves of the plate rejoined along a seam behind the head On the bench
The finished plate stood up in daylight, the fish cleaned and the join closed Finished
03

Priscacara Prep (Priscacara serrata)

Prepared independently over five days. This Priscacara serrata from the 18-inch layer took about 6 hours and 40 minutes to prepare. I started by using an air scribe to “rough out” the shape of the fish, then I followed up with air abrasion to finish the prep. The photographs are the same slab in the same position each time, so stepping through them shows only what came off between sittings.

A small square limestone slab held in one hand, with only a faint dark trace visible near the centre
Only a faint trace at the surface.
The same slab with a fan of fin rays and part of a spine now exposed
Fin rays and part of the spine out of the matrix.
The same slab further along, with more of the body and the head area exposed
More of the body, and the head starting to show.
The same slab at the end of the session, the fish exposed from head to fin
Head clear, and the outline of the fish readable end to end.
04

Columbian Mammoth Rib (Mammuthus columbi)

Prepared for the Mammoth Site of Hot Springs, South Dakota. Catalog number MSL 2855 arrived as a tray of broken fragments. The pieces were joined with Paraloid B-72 and stood upright in a sand tray so each join could cure without stress on the bone. Too much of the middle was missing to close the gap, so that section was left open rather than filled. The finished rib was housed in a custom plaster support jacket.

Mammoth rib fragments in a specimen tray before preparation Before
Rib sections standing in a sand tray while adhesive cures During
Reassembled mammoth rib on the preparation bench After
Finished mammoth rib resting in its plaster support jacket Plaster jacket
05

Columbian Mammoth Vertebra, Cavity Mount (Mammuthus columbi)

Made for the Mammoth Site of Hot Springs, South Dakota. The mount is carved to the shape of this vertebra, so the bone sits in full contact with its support and can be handled and stored without pressure on the processes.

Mammoth vertebra seated in a custom-carved cavity mount Cavity mount
06

Knightia (Knightia eocaena)

Prepared independently with an X-Acto knife. An Eocene fish from the Green River Formation that came out of the quarry with much of the body still buried. The limestone above it was lifted a flake at a time until the head, body, and fins were all clear of matrix.

Knightia fossil fish partly covered by limestone matrix Before
Fully exposed Knightia fossil fish after preparation After
07

Diplomystus (Diplomystus dentatus)

Prepared independently with an X-Acto knife. Only part of the fish showed on the split surface. Hand preparation brought up the rest of the animal, including the deep-bodied outline and the fin rays. The rays are thin enough that a slip takes them off the slab for good.

Diplomystus fossil fish before preparation, much of the fin detail still under matrix The same Diplomystus after preparation, tail fan and fin rays fully exposed

Drag the handle, or focus it and use the arrow keys

08

Olenellus (Olenellus getzi)

Prepared independently, cleaned and glued. I collected this Olenellus getzi from the Kinzers Formation of Pennsylvania. The rock this trilobite rests in was covered in mud and fragmentary when found. I used brushes to clean the mud, and then I glued the trilobite back together.

Broken shale containing an Olenellus trilobite in the field Before
Cleaned and reassembled Olenellus specimen block After
09

Flexicalymene (Flexicalymene retrorsa)

Prepared independently with air abrasion and a scribe. Nothing was visible on the surface of this slab when work started. Air abrasion and scribe work took the overburden down in stages until an Ordovician trilobite came up intact, sitting just below the face of the rock.

Slab with no fossil visible at the surface before preparation Before
Flexicalymene trilobite exposed on the slab after preparation After