Rare 4″ Fossil Ammonite Stemmatoceras frechi | Jurassic Middle Bajocian Somerset UK | Genuine + COA

Description

This listing features a rare 4-inch fossil ammonite, Stemmatoceras frechi, from the Middle Bajocian Stage of the Jurassic Period, found in the Bruton Cole Syncline, Somerset, United Kingdom. The photo shows the actual specimen you will receive. Each cube in the scale image equals 1cm — please see the image for full sizing.

This is a scientifically important and beautifully preserved ammonite, ideal for collectors, academic study, or museum-quality display. It comes from a classic Lower to Middle Jurassic site in southern England, rich in ammonite faunal zones.

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity.

Geological & Scientific Information:

• Fossil Type: Ammonite
• Species: Stemmatoceras frechi
• Order: Ammonitida
• Superfamily: Stephanoceratoidea
• Family: Otoitidae
• Geological Stage: Middle Bajocian (approx. 168.3 – 166.1 million years ago)
• Biozone: Likely part of the Humphriesianum Zone, a key ammonite zone in the upper Bajocian succession
• Period: Jurassic
• Locality: Bruton Cole Syncline, Somerset, England, UK
• Depositional Environment: Shallow epicontinental sea within the Wessex Basin, composed of marl and limestone beds deposited under low-energy conditions

Morphology & Notable Features:

• Moderately evolute shell with partially exposed inner whorls
• Ribbing is strong, bifurcating at the umbilical shoulder and extending prominently across the flanks
• The venter is rounded to slightly keeled, often without tubercles
• Typical of Stemmatoceras, the ornamentation is clear and the suture lines may be visible in well-preserved specimens
• The genus is known for being transitional in form between early Bajocian Otoitid ammonites and later more strongly ribbed Stephanoceratoids

Scientific Significance:

Stemmatoceras frechi is a notable species within the Middle Bajocian ammonite succession, helping refine zonal stratigraphy across southern England and Europe. Its presence in the Humphriesianum Zone aids in correlation with other fossiliferous Bajocian marine sequences.

Originally described during 19th-century monographic studies on European Jurassic ammonites, this species is now relatively rare in the fossil trade and highly prized by both academic and private collectors.

Ideal For:

• Ammonite and fossil collectors seeking classic British material
• Educational and research collections focused on Jurassic stratigraphy
• Natural history and paleontology exhibits

What You Will Receive:

• The exact Stemmatoceras frechi fossil shown (4″)
• Certificate of Authenticity
• Secure, protective packaging to ensure safe delivery