The water-ice-rich north polar layered deposits (NPLD)of Mars play a key role in the Martian climate throughan active exchange of water vapor with the atmosphere.Conditions are not currently amenable for flow of theNPLD; however, gross morphological evidence for pastflow suggests the possibility of a warmer climate in thepast. Here we present the first comparison of internalstratigraphy predicted by a flow model with that observedby an orbital radar sounder. We have analyzed radar datafrom Gemina Lingula, the southernmost tongue of theNPLD, acquired by the Shallow Radar on board NASA’sMars Reconnaissance Orbiter. The data shows extensiveinternal reflections and several radar reflectors weremapped to create gridded surfaces of this part of the NPLD.All the mapped radar reflectors were smooth with nosudden dips towards the surface or the bedrock. Theinternal radar reflectors were then compared with modeledisochrones in two different areas of Gemina Lingula underthe assumption of flow occurring. Results indicate that flowof ice is unlikely to have occurred between the main domeand Gemina Lingula. Furthermore, we found no evidencefor the existence of a prior ablation zone in Gemina Lingulaas predicted in another study.