[R-sig-Debian] libRblas.so: cannot open shared object file: No such file or directory

[Steve Gutreuter]

R 3.5.1 is installed under Linux Mint 19 from binaries r-base and 
r-base-dev from ubuntu bionic-cran35.  Mysteriously, packages using 
libRblas cannot be compiled.  I get: libRblas.so: cannot open shared 
object file: No such file or directory.  And indeed, I find no libRblas.so.

Any ideas about how to fix this?

Thanks,

Steve