Glacial drift or not – that is the question here !

Over the last couple of years, a couple of friends and myself have, more or less independently,  found relatively substantial blocks with nicely preserved, large Echioceras raricostatum, always at around the same spot, in Bay. Echioceras is rather rare by itself in Bay, if found, mostly flattened, so a find of a 3D calcite-preserved Echioceras block is something quite rare. We´ve been discussing the question if the blocks are

  • glacial drift, derived from the boulder clay
  • or special preservation e.g. from a localized lens, from an old cliff fall in that area
Unless we find such a lens in-situ, the question will probably remain un-answered.
Whatever the source, the ammonites are rather nice, but relatively difficult to prep. The matrix is full of small and large ammonites, crinoid remains, bivalves etc and is rather sticky. Here is an example that a friend (you know who you are) presented to me as a (generous) gift.
Echioceras raricostatum, 6 cm

Echioceras raricostatum, 6 cm

Echioceras raricostatum, keel detail

Echioceras raricostatum, keel detail

Interestingly, HOWARTH notes that for the holotype of SIMPSON´s Echioceras cereum (a synonym for E. raricostatum), that the exact bed ist not known – the preservation looks exactly like the ones from the block !
This is a block I´ve found myself, and begun preparation, a large E. cf. raricostatoides (about 8 cm)  is visible.
Block with Echioceras cf. raricostatoides, ammonite about 8 cm

Block with Echioceras cf. raricostatoides, ammonite about 8 cm

This is another one, awaiting preparation, found on my birthday this year !
Block with Echioceras sp., size about 40 x 20 cm

Block with Echioceras sp., size about 40 x 20 cm

Not breaking these kinds of blocks on the beach is always some kind of gamble, you have to carry it a long way, but you might end up with a block with only the partial, ground down ammonites showing on the surface… we´ll see how this one turns out…
AndyS
Leave a comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: