Crab Concretion Identification Tips

[McHorse]

Hi All,

 

I am a rookie fossil hunter here in New Zealand looking and one of my goals is to find a crab. I always seem to come back with bits of bone but never a crab.

 

I think the problem for me is identifying a round rock, amongst all the other round rocks on the beach that may hold a crab. 

 

I could go down to my local rock shop and buy a crab. However you can't buy the experience of actually finding one. 

 

I am hoping some of the more experienced can offer some tips and tricks for identifying possible fossil bearing concretions.

 

When I go out hunting the things I look for are:

• Round or Kidney shaped rocks.

• Sandstone with no signs of metamorphosis.

• Signs of legs sticking out.

 

My questions are:

• Are crabs more likely found in hard or soft sand stone or both?

• Is there a particular colour matrix I should look for?

• Are crabs often found with other fossils such as shells? Or a crabs generally covered in off shore sediments away from shells?

 

[DLB]

i could be wrong but ive heard that there off shore and you should collect or look for them at low tide. but im not a expert on newzeland crab.here we find them in soft matrix as wellas hard the hard matrix usally have a better preserved crab in them. i usally dont see shells in with the crab so i would presumably guess that is another signe that they are off shore as well.

[jpc]

Have you looked for crabs at Glenafric?  I was there 30 years ago and found a few in big cannonball shaped concretions.  They are a ton of work to prep once you do find one.  

[McHorse]

Hi guys thanks for you reply. I have not been to Glenafric yet only Motunau. That will be my next port of call.

 

Could you give me a description of the matrix of the ones you found jpc?