Ancient sea lilies

I got side-tracked from looking at rocks by a trip to the wharf. But there was something I'd discovered among the information about pillow lavas.

This turtle has been sitting on the shelf above my desk for a while.

Carved stone turtle full of fossils

I had wondered what made those circles and stars in the rock. The pdf on the geology of Strathcona Park had a section describing their source: sea lilies.

The other side of the turtle

The circles are sections of the stems of a marine animal, crinoids, animals related to starfish and sea urchins. (The five-pointed star hints at this relationship.) They come in many forms, stalked and unstalked. The stems are made of discs of calcium carbonate. When the rest of the animal disintegrated, the mineral part of the stem remained. So what I'm seeing is cross-sections of crinoid stems.

Five-pointed star shape of the centre of a stem disc.

The crinoid column is also called a stem or stalk. The stem is made from disc-shaped pieces of endoskeleton which are stacked upon each other and are hollow in the middle. They are held together by ligaments which decomposed rapidly after death. The hollow shapes inside of the discs include: elliptical, circular, pentagonal, and star-shaped. (fossilera.com)

The turtle has two carved fishes on the top of its carapace. A reminder that the content of the stone was once underwater?

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Había estado viendo piedras (lava almohadillada) cuando lo dejé para subir fotos de alga marina y sus residentes. Pero me quedó una cosa por mencionar.

Esta tortuguita de piedra vive en el estante arriba de mi escritorio. Siempre me ha inspirado curiosidad: ¿qué criatura o proceso hizo estos círculos y estrellas?

En el documento acerca de la geología de esas lavas almohadilladas, encontré su descripción; son parte del esqueleto de unos animales marinos que vivían en este sitio cuando todo estaba al fondo del mar. Se llaman lirios marinos, o crinóideos, animales del grupo a que pertenecen las estrellas de mar y los erizos de mar.

Los animales pueden estar fijos a la roca o pueden alzarse sobre tallos. Estos tallos están hechos de discos de carbonato de calcio. Cuando el animal se muere, se desintegra, dejando solamente estos discos.

El centro del segmento puede tener el espacio en forma de círculo, pentágonos, o estrellas, con cinco puntos.

La tortuga tiene encima del carapacho, dos pescados. ¿Un aviso que lo que contiene la piedra alguna vez vivía bajo el mar?

IRFD update: lizard, fossil, more!

Here are another seven happy Rock Flippers, who posted on Twitter at #rockflip:

Michael ‏@akmrbaldwin
Happy Int'l Rock Flipping Day from Alaska - a carabid beetle! #rockflip #IAmANaturalist pic.twitter.com/C7IrrL6n0D

Lobo Guará ‏@juandoso
Hidden treasures! pic.twitter.com/UcvzHVJqGs

Rebecca Zarazan Dunn ‏@rebeccazdunn
Happy International Rock Flipping Day  pic.twitter.com/8vGF2abNuF

Janet K C ‏@jkricketc
Just the usual dinosaur AKA Western fence lizard. pic.twitter.com/oQRg4kmJEZ

Jesse Calhoun Bethea ‏@jesscalhoun
Adventuring in Glen Echo Ravine for #rockflip day. pic.twitter.com/0UhD9xSbAL
Melissa found a fossil. pic.twitter.com/r5GEIpqYFx

Earthworm pic.twitter.com/h2BQHK4xTH

Catherine Scott ‏@Cataranea
Happy international rock flipping day! Perhaps you might find a beautiful spider! [photo by @Ibycter] pic.twitter.com/U3XHWoph7j

Laura ‏@lkwagonlander
September 14, 2014 http://pic-collage.com/_r4br8K49 pic.twitter.com/l2YpKZ6CIO

(This has a Rock-flipping kid.)

A couple of others also posted their photos on Twitter, but they had also added them to the Flickr pool, so they're on the first list, which I'll repost here:

• From Pennsylvania, Kate of Outside My Window participates in IRFD… without flipping a rock! I guess we’ll allow that, especially since she found some nifty spider webs and a small mammal.
• Here in British Columbia, I (that's Heather - ed.) did flip rocks, and after many tries turned up a couple of worms and a pill-bug (or something like one, anyway).
• Elsewhere in the province, (I, Susannah) face similar challenges with dry rocks, but still manage to find a few things, including (unfortunately) some non-organic debris.
• And to the south in Washington state, Dave Wenning of Wild Fidalgo flips rocks on the beach (and in his garden) and finds several Purple Shore Crabs. And a few other things. Even if he didn’t look very dignified doing it.
• Bill finds several critters under his rocks, including a beautiful millipede. (A beautiful millipede? Well, I think it is.)
• The WNY meet-up page includes a number of rock flipping discoveries, such as a lovely speckled salamander and a pair of slugs from Barbara Newman H., and a pretty black beetle and another salamander from Mark. I’m jealous – I wish I could have found a salamander!

Over in the International Rock Flipping Day Flickr group, many more interesting things have been discovered:

• Sara Rall flipped paving stones and came up with a good variety of small critters, including a rove beetleand a ground cricket. 
• Rob Cruikshank found ants and pupas, and a cute white springtail.
• Paul Fehringer, of Wild Spirit Education, found a red-legged beetle, and a strange (to me) centipede.
• And John Beetham found a spider with the intriguing name of Amaurobius ferox. Among other beasties.

An oldie but a goodie

We don't have to go to the beach to find intriguing marine invertebrates. Last Sunday, we went to an antique fair, and I came home with an ammonite from Madagascar, split in two to show the chambers.

The two halves, face to face.

The ammonites were prehistoric crustaceans, living at the same time as the dinosaurs, and going extinct with them. They are related to our modern squids and octopuses, and more remotely, to the nautilus, which they looked like.

Artist's reconstruction of Astroceras. Wikipedia, art by Nobu Tamura (http://spinops.blogspot.com)

Fossilized ammonite shells can be found all over the world, with an interesting lode occurring just "next door", in Alberta; these can be highly iridescent, and are sold as gemstones. Others may be filled with chalk, sandstone, pyrite; whatever sediment and minerals are prevalent in the layer where the ammonite is found. My son has an uncut ammonite he found on a mountainside, a charcoal grey, fist-sized, coiled lump of granite. The fossils show up in all sizes, from 1 mm. to over 6 feet across. Mine measures just over 3 inches.

The animal lived in the front end of a series of chambers (camerae), divided by curved walls from the older ones. As the creature grew, always moving to the new room on the front, it sealed off the inner chambers, except for a thin connecting siphon, creating a sort of flotation device that could be filled with water or gas as needed to rise or drop in the water column.

The meaty part of the animal was not often fossilized; what we find are the empty shells, now filled with an assortment of minerals.

Beyond a tentative ink sac and possible digestive organs, no soft parts are known at all. They likely bore a radula and beak, a marginal siphuncle, and ten arms. (Wikipedia)

Sometimes the fossils contain smaller fossils: the animals that the ammonite had eaten, giving us a clue to their life style.

Ammonites were the predators of their time, feeding on most living marine creatures including molluscs, fish and even other cephalopods. By analogy to modern cephalopods, their method of attack probably comprised of silently stalking their prey, then rapidly extending their tentacles to grasp the target. Once caught the prey would be devoured by the ammonite's powerful jaws, located at the base of the tentacles, between the eyes. (From Discovering Fossils.)

This I learned from the web. What can I learn from the critter in hand, itself?

Closer view, showing half the diameter of the shell.

The outer chambers are filled with fine sandstone, with a few larger grains spotted about. Each chamber is divided off by a wavy wall (septa). As we move to the internal sections, the filling changes to crystallized stone, in varying tones of red, and translucent. (That inner spiral looks like sugared fruit; appetizing, but hard on the teeth!) Several chambers are hollow, lined with sharp crystals, slightly purplish, a pale amethyst hue. There seem to be the remains of communication pipes through the walls.

Zooming in on a pair of chambers. Two tubes enter or leave each side of the chamber.

I wondered why there was such a difference in the filling material. Why are the larger chambers filled with sand, and the inner ones with crystal? Back to the web . . .

The body chamber is the final, longest chamber, in which the ammonite animal actually lived. It is not divided by sutures and is often fossilised in a different colour to the phragmocone chambers, as sediment readily filled it after the creature died and its soft parts rotted away. The chambers of the phragmocone however, are largely sealed off from the body chamber, and because of this they are usually mineralised over a longer period, due to percolation of mineral rich water through the shell. (From An Introduction to Ammonites, UK Fossils.)

There is still more variation; each of the larger chambers has collected its own load of sediment, and seepage has tinted the outer sections, creating beautiful patterns.

Detail of first and second chamber filling.

Ammonites from Madagascar and Alberta can be iridescent. This one is from Madagascar. Unfortunately, it is badly worn, and only hints of the iridescent coating are left on the outside of the shell; glints of red and green along the broken edges.

Iridescent ammonite, from Wikipedia.

Very Big, BIG, Beetle

We've been told that the beach below our motel in Campbell River is a favourite site for fossil hunters. With that in mind, when I saw this ...

... I was immediately convinced that it was a humongous fossilized beetle.

Well, not exactly convinced. Not really. Not even slightly. But I do have a good imagination.

The "head" is over a meter long. The antennae are longer still. The rock is just one of the great slabs of sandstone that cover the beach. The green fuzz on it is rockweed.

And don't forget; September 9th is Rock Flipping Day! Pass it on!

Of chewed wood, rock stencils, and walking on water

Our last trip to Crescent Beach was so productive that we went again this Sunday, in expectation of more great finds. Unfortunately, the tide was nearing its peak, and the remaining beach was lifeless. So was the water surface; nary a bird to be seen.

So we looked at rocks and logs, instead.

Empty sea, empty sky. On the left, the steps from 24th street, at the top of the cliffs, drop down to beach level.

Most logs float in without much damage, but every so often one looks as if it had been chewed.

Black rot or burn marks on a stump.

Beach rocks often incorporate chunks from various sources, creating interesting patterns, good imagination boosters. Laurie says these look like footprints; I see the whole section as a fish stencil.

And this is a pair of animals hiding behind a stump and keeping a watch out left and right.

Ok, now I'll be sensible. Is this a fossil of some kind? The rest of the rock is plain, smooth stone.

Something alive on shore; orange jellies on a blackened, rotting log.

Something alive on the water, after all; a man on a paddle board.

I grew up in boats, playing in skiffs and canoes. I'm fascinated by these paddle boards; it's almost like walking on water. I see people off on the horizon, standing on what looks like nothing at all, or skimming along silently, approaching those distant rafts of diving ducks, and I envy them.

I just looked up the price of one; over a thousand bucks. And I'd never get Laurie on one, anyhow. I'll contain my envy.

A Skywatch post.