Here we go at last with what I reckon is a Perisphinctes teased from the base of the cliffs at Port-en-Bessin in the department of Calvados in Normandy. Apologies for the flash washing out a lot of the detail but you can see where the ribbing divides towards the keel on the left. Feel free to suggest otherwise !

Keef

http://www.tonmo.com/forums/attachment.php?attachmentid=1649&stc=1&d=1131814010

here it is again but wet ! hope it helps

Keef

http://www.tonmo.com/forums/attachment.php?attachmentid=1651&stc=1&d=1131815030

Wow! That's just beautiful!

Great fossil Keef. The washed out pic shows the rib bifurcations better, and the wet one shows the rest better :thumbsup:

Any idea what that shiny thing is in the first pic (to the upper left of the ammonite):?:

thanks Sorseress, glad you like it !

Kevin, "bifurcation" nice word ! I new there'd be a proper term but couldn't be asked to scour the journals ! the wee shiny thing is a small clam shell, the slab is about 18" x 12" & full of goodies but as yet is still in its "just left the beach" state. The other round fella at 9 o'clock is a bivalve which is almost solid calcite & a preparators dream as they just pop out of the matrix complete, but who cares :lol: <-- fossil snob

Keef

hey, I gone bin promoted too, no Jag for me though !

Spartacus truly has a knack with the old Horns of Ammon, yet another fantastic specimen.

Perisphintes factoids for you: Unlike the Jacksons, this form shows great sexual dimorphism. The macroconchs are very large with strong wedge-shaped ribbing towards the aperture, but the microconchs are much smaller with unmodified ribbing and lateral lappets in the final aperture. Also, they are only known from the Jurassic Oxfordonian, i.e 159-154 mya, though they are found all over the world.

There you go.

thanks for the gen. most erudite one !
there's more to come from the "Falaises des Vaches Noires" in Calvados (also Oxfordian) & the recent haul from Longeville-sur-Mer, here in the Vendée (the big ones)

Keef

Unlike the Jacksons, this form shows great sexual dimorphism.

ROFL.