"We found sandstone that carries grains and rock fragments created far from Jezero Crater - and a mudstone that includes intriguing organic compounds," Perseverance Project Scientist Ken Farley of the California Institute of Technology said in the release.
Perseverance has analyzed the rock samples and confirmed that they feature a class of organic molecules that are spatially correlated with those of sulfate minerals, the release said.
"The fact [that] the organic matter was found in such a sedimentary rock - known for preserving fossils of ancient life here on Earth - is important," the release added.
The rover has collected four samples from an ancient river delta in the Jezero Crater since July 7, bringing the total count of scientifically compelling rock samples to 12, according to the release.