Potential fossil material help with identifying

[Morechai]

Area with extensive sandstone,  but no clear signs of fish, shells etc.  Wondering if these examples of two different material formations may be of organic origin?

[Rockwood]

I doubt that this can be called a fossil. It looks like either chert or carbonate concretion. Both materials may be of organic origin, but the form has not been conserved. 

[ynot]

These look like pieces of limestone (light grey) with concretions (dark brown) and differential weathering.