Allan Hills (image) University of Washington Share Print E-Mail Caption The Allan Hills has older, blue ice exposed at the surface. Researchers towed their instrument on this wooden sled. The sloping topography and slippery surface made it challenging for radar surveys. Credit Laura Kehrl/University of Washington Usage Restrictions With credit Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.