Carter et al. (1963) report the occurrence of lavas about 3 km west of Lamja that are within Cretaceous Numanha shales. They are spheroidally weathered and in thin section reveal altered phenocrysts of olivine, abundant calcite and analcime with a groundmass of iddingsite, cloudy plagioclase laths and magnetite. Nepheline is reported as sometimes being present with a few samples containing leucite. Wright (1976) is suspicious about the accuracy of the identification of the last two minerals.