<![CDATA[1A Collections]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/browse?sort_field=added&page=8&sort_dir=a&output=rss2 Tue, 09 Apr 2024 21:23:01 +0100 p1acollections@esc.cam.ac.uk (1A Collections) Zend_Feed http://blogs.law.harvard.edu/tech/rss <![CDATA[TF0321 Ammonite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/75

Title

TF0321

Ammonite

Description

Species

Dactylioceras commune

Stratigraphic Range

Jurassic

Taxonomy

Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida

Distinctive Features

Ribs
Imprint of inner whorls visible
Curved shape (part of coil)

Preservation

Pyritised shell replacement
TF0321_HS.png
TF0321_sketch.png
]]> Thu, 20 Jun 2019 09:46:09 +0100 <![CDATA[TF0311 Ceratite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/76

Title

TF0311

Ceratite

Description

Species

Ceratites

Stratigraphic Range

Triassic

Taxonomy

Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ceratitida


Distinctive Features

Planispiral
Aperture
Body chamber
Ceratitic suture lines
Evolute

Preservation

Internal mould

Advanced notes

Set 1 specimen is a plaster cast
TF0311_HS.png
TF0311_sketch.png
]]> Thu, 20 Jun 2019 09:48:59 +0100 <![CDATA[TF0301 Goniatite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/77

Title

TF0301

Goniatite

Description

Species

Goniaites

Stratigraphic Range

Devonian to Permian

Taxonomy

Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Goniatitida

Distinctive Features

Planispiral shell
Goniatitic suture lines
Involute

Preservation

Internal mould
TF0301_HS.png
TF0301_sketch.png
]]> Thu, 20 Jun 2019 09:51:40 +0100 <![CDATA[TF0331 Ammonite Aptychus]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/78

Title

TF0331

Ammonite Aptychus

Subject

Location

Kimmeridge Clay, Roslyn Pit, Ely

Description

Species

latus Parkinson

Stratigraphic Range

Jurassic

Taxonomy

Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida

Distinctive Features

Straight edge
Growth lines
Curved plate

Preservation

Calcite
Disarticulated from ammonite shell

Advanced notes

One could be forgiven for thinking, at first glance, that this was the valve of a bivalve mollusc. However further interrogation of the fossil: the shape, the fact that the growth lines are on one side of the shell but there is no sign of adductor muscle scars, palial sinuses or other characteristic bivalve signs, and the 'bobbled' texture on the plate, leads us to the conclusion that this is not from a bivalve.

Rare examples of ammonite shells with aptychi preserved articulated have shown these plates to be located in the body chamber of ammonites. Upon death most pairs of aptychi disarticulate and hence they are found as single plates, such as this one.
TF0331_HS.png
TF0331_sketch.png
]]> Thu, 20 Jun 2019 09:59:02 +0100 <![CDATA[Ammonoid]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/79

Title

Ammonoid

Description

Taxonomy

Phylum: Mollusca

Class: Cephalopoda

Subclass: Ammonoidea

Diagnostic features

[See labelled diagram above]

Aragonite shell

Septa

Suture (different for goniatites, ceratites and ammonites, see second diagram above)

Chambers

Siphuncle

Planispiral shape, involute or evolute (see third diagram on right hand side)

Stratigraphic range

Devonian to Cretaceous

Way of life

Nektonic (jet propelled)

Predatory

Marine

Common preservation

Internal mould

Learn about types of preservation

Advanced notes

Ammonoids could passively remove or add water to chambers via the siphuncle. This allowed them to change their density, and maintain neutral buoyancy with the surrounding seawater. This meant that they were able to swim as efficiently as possible.

Ammonoids are extremely good index fossils on account of their diverse morphologies, good preservation potentials and widespread fossil locations.

Specimens

Browse ammonoids

External links

Telling planispiral fossils apart

ammonoid_sketch.png
ammonoid_suture_sketch.png
ammonoid_sketch_2.png
]]> Thu, 20 Jun 2019 10:01:51 +0100 <![CDATA[Belemnite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/80

Title

Belemnite

Description

Taxonomy

Phylum: Mollusca

Class: Cephalopoda

Subclass: Coleoidea

Cohort: Belemnoidea

Diagnostic Features

Diagram with labelled features of belemnites

'Bullet' shape

Phragmocone: chambers divided by aragonitic septa (often preserved as conical cavity)

Radial calcite crystals form the guard

Way of life

Nektonic

Predatory

Marine

Advanced notes

Exceptional preservation of belemnites showing soft parts has shown them to be very similar to squid in shape. The guard and phragmocone were held inside the soft parts of the animals, acting as a kind of backbone.

Because the phragmocone is made of aragonite it is often not preserved. In contrast the calcitic guard is very often preserved. This means that a common preservation of belemnites is of the guard with a conical hole where the phragmocone once was. This empty conical chamber is often crushed.

Specimens

Browse belemnites

External Links

Mollusc World

Learn about types of preservation

belemnite_sketch.png
]]> Thu, 20 Jun 2019 10:11:20 +0100 <![CDATA[TF0401 Belemnite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/81

Title

TF0401

Belemnite

Description

Stratigraphic Range

Carboniferous to Cretaceous

Taxonomy

Phylum: Mollusca
Class: Cephalopoda
Order: Belemnitida

Distinctive Features

Guard of radial calcite crystals
Conical cavity where phragmocone used to be

Preservation

Aragonitic phragmocone dissolved
Sediment infil of conical cavity where phragmocone used to be (set 1 only)
TF0401_HS.png
TF0401_sketch.png
]]> Thu, 20 Jun 2019 10:18:03 +0100 <![CDATA[TF0402 Belemnite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/82

Title

TF0402

Belemnite

Description

Stratigraphic Range

Carboniferous to Cretaceous

Taxonomy

Phylum: Mollusca
Class: Cephalopoda
Order: Belemnitida

Set 1:
Group: Cylindroteuthis
Set 2:
Group: unknown

Distinctive Features

Guard with radial calcite crystals
Crushed conical hole where phragmocone used to be
Long, near cylindrical shape

Preservation

Dissolution of phragmocone
Sediment infill of conical cavity where phragmocone used to be
Crushing of infilled phragmocone area
TF0402_HS.png
TF0402_sketch.png
]]> Thu, 20 Jun 2019 10:20:13 +0100 <![CDATA[TF0403 Belemnite]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/83

Title

TF0403

Belemnite

Subject

Location

Oxford Clay, Warboys Pit, St Ives

Description

Species

Hastatus

Stratigraphic Range

Jurassic

Taxonomy

Phylum: Mollusca
Class: Cephalopoda
Order: Belemnitida
Genus: Hibolites

Distinctive Features

'Bullet' shape
Guard with radial crystals
Hollow phragmocone area

Preservation

Mineral replacement of calcitic guard
Dissolution of aragonitic phragmocone
Sediment infil of phragmocone area

Advanced notes

Hibolites are not as bullet shaped as most belemnites, and at first glance could be confused with an Echinoid spine. However the radial arrangement of crystals and the presence of a hollow region where the phragmocone would once have been allows us to, after some examination, confirm these specimens as belemnites.
TF0403_HS.png
TF0403_sketch.png
]]> Thu, 20 Jun 2019 10:22:31 +0100 <![CDATA[TF0404 Belemnite Peel]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/84

Title

TF0404

Belemnite Peel

Description

Taxonomy

Phylum: Mollusca
Class: Cephalopoda
Order: Belemnitida

Distinctive Features

'Bullet' shape
Conical hole where phragmocone used to be
Radial crystals (here in cross section)

Preservation

Peel of a cross section through a belemnite (manmade)

Advanced notes

Have a look at this specimen under a microscope. The peel allows us to see very fine details.
TF0404_peel.png
TF0404_sketch.png
]]> Thu, 20 Jun 2019 10:55:47 +0100