Cystoid, Blastoid, Or Crinoid?

[z10silver]

Found by a friend in the Mojave Desert. I wasn't sure if this was a cystoid, blastoid, or crinoid - or something else? I appreciate the help.

-Zach

[piranha]

My vote: Crinoid

[z10silver]

That was my initial guess but I thought arms would be visible if it were a crinoid? To me the end just looks like a homogenous blob.

[trilobiteruss]

I would lean towards some type of cystoid myself.

[Rockwood]

I would lean towards some type of cystoid myself.

Second that.

[Al Dente]

It doesn't look like echinoderm to me. My guess would be a cross section through Receptaculites.

[FossilDAWG]

I very much agree with Al Dente. Definitely a recepticulitid.

Don

[trilobiteruss]

I wondered about the Receptaculites myself, but it was an odd slice so I was not sure. I think Al Dente may be right on this one, but boy the section sure had a cystoid like outline look to it, interesting!

[araucaria1959]

I agree with Receptaculites; the purported "crinoid" or "cystoid" stalk is in fact a crosscut through a flat receptaculite in 90° angle.

Here is a link to a similar specimen:

http://www.google.de/imgres?q=Receptaculites&num=10&hl=de&tbm=isch&tbnid=VJUASXcwcTJT3M:&imgrefurl=http://www.niagaracave.com/album.asp&docid=fyTcTcVOEZp2vM&imgurl=http://www.niagaracave.com/Images/Receptaculites1.jpg&w=2560&h=1920&ei=-O2OUIj8BojFswbCrIHQCw&zoom=1&iact=hc&vpx=940&vpy=134&dur=1031&hovh=194&hovw=259&tx=149&ty=110&sig=113554381529417563262&page=1&tbnh=153&tbnw=220&start=0&ndsp=21&ved=1t:429,r:9,s:0,i:99&biw=1246&bih=857

araucaria1959

[araucaria1959]

The link in my post above leads to the general website; here is the link directly to the picture:

http://www.niagaracave.com/Images/Receptaculites1.jpg

araucaria1959

[z10silver]

interesting, thanks!

[Missourian]

Very interesting structure within the fossil.

Can a cross section be seen where it fractured?