[R] Recursive Indexing Failed

[Alaios]

Dear all,
I would like to ask your help concerning an error message I get.

I have the following struct

str(CRagentInTime[[1]])
List of 2
 $ timelag: int 0
 $ CRagent:List of 50
  ..$ :List of 3
  .. ..$ CRmap: num [1:256, 1:256] NA NA NA NA NA NA NA NA NA NA ...
  .. ..$ xy   : num [1:2] 10 177
  .. ..$ sr   : num [1:49] -94.9 -92.8 -79.5 -97.6 -78.4 ...

and I wanted to select all the sr fields for every of each one of the 50 CRagent Lists I have.

So I tried something like

str(CRagentInTime[[1]][[2]][[1:10]]$sr) and I get a message that
Error in CRagentInTime[[1]][[2]][[1:10]] : 
  recursive indexing failed at level 3



strange to me is that this one works

str(CRagentInTime[[1]][[2]][[1]]$sr)
 num [1:49] -106 -92.9 -101.3 -81.9 -96.7 ...


I would like to thank you in advance for your help
Best Regards
Alex