Tips to find complete crinoids?

[Jurassicz1]

So i might soon be heading to a silurian site. It has shells trilos crinoid stems. But i would really want to find a complete crinoid. Any tips how? Split rocks open? Look in areas where theres alot of crinoid stems? 

[Fossildude19]

It is really a matter of luck, and what is historically found at the site. 

Should you split rocks, ... yes. 

Should you look carefully at already broken matrix, ... yes. 

There is no proven method to find complete crinoids.

 

There is no guaranteed way to find complete crinoids. 

I have found that most of my crinoid finds are what are commonly found - stems, individual columnals, lumen casts, and holdfasts.

I only have one calyx that I am positive of. 

 

Good luck. 

 

[Bob Saunders]

Complete crinoids are rare and usually after much prep work. I agree about looking at already broken matrix. someone may have left a good piece because it was only slightly exposed and did not realize the potential. 

[FossilDAWG]

As has been said, there is no certain way to find intact crinoids.  However it can help to think about the conditions that are required to preserve these delicate animals intact.  If they are exposed after death for more than a couple of days they start to break up.  Just as important, they will be attacked by scavengers and rapidly broken to bits.  So for a crinoid to be preserved intact (stem, calyx, and arms) they need to be buried quickly.  Deposits with lots of disarticulated stem pieces (or short segments) and cup plates indicate a good biological environment for crinoids but they are not buried quickly enough to be preserved intact.  Often these deposits are also current sorted so only bigger pieces are heavy enough to resist being washed away.  If you see pieces of arms, better yet with pinnules still attached, that is a very good sign as it means the animals were buried quickly enough to keep fragile bits together.

 

Often, intact crinoids were smothered under a deposit of sediment, often a sediment flow down a submarine slope, generated by a storm or even earthquake.  These deposits are often coarser than the sediment they are lying on top of.  So look on the underside of (or within) thin limestone/sandstone/siltstone lenses or layers in a deposit that mostly consists of fine grained sediment such as shale.  If the crinoids are swept up in the sediment flow they may show on the top as well.  Intact crinoids are usually very patchy in their distribution, so you can focus your efforts by looking for concentrations of long pieces of intact stems or arms; if you see these then complete specimens may be nearby.

 

It is worth mentioning that some crinoids, especially camerates, had robust calyxes of fused or tightly linked plates.  These calyxes could hold together even when the stems and arms disarticulated, and they could resist strong currents.  So if you find a deposit of stem segments, especially in Carboniferous rocks, be on the lookout for calyxes even if finding specimens with the arms and stem are unlikely.

 

Don

 

[RuMert]

"The finding of sea lilies is well predictable. For a successful search, signs are used that lead to a "crinoid bank". When working on it, its resource is very small, but the output is effective in terms of variety or quantity. Actually, sea lily hunters follow these unwritten signs. In other cases, the finds are really considered random, etc. But I will immediately explain for those who think that having arrived there he will find what he is looking for - this is a laborious process that takes more than one day, in terms of work, and besides, it is necessary to really understand the logic of biofacies when comparing the relief of the seabed. Read the literature, where facies of the seas of the past are characterized. Much of what you read will help in successful research. Of course, questions about the characteristics of such "banks" never find an answer for well-known reasons" (c)

From a post I stumbled upon on a local forum (translated). I never knew if the guy was just bragging or there was indeed an "art" of finding crinoids (nor I ever searched for crinoids in Paleozoic sediments) but I liked the Lovecraftian spirit of that hidden knowledge

 

[Jackson g]

I would research the locality, and see what crinoid taxa are available. I can find complete calyxs about every time I go hunt, but the specific area is also a high energy depository setting, so it takes a good amount of effort to find one complete, and not crushed or just a partial. A rule of thumb I go by is searching the scraps of encrinite stone formations first. You can split as much rock as you want, but heading towards the bottom of the formation can show what's already weathered out of the rock. I wouldn't necessarily say look where there are just crinoid stems, many a blocks will have thousands of stems and no calyx. Luck and experience really would help you here.