DISCOVERY OF LOWER BERRIASIAN (LOWER CREATACEOUS) AMMONOID GENUS ARGENTINICERAS FROM KACHCHH (INDIA) AND ITS RELEVANCE TO JURASSIC CRETACEOUS BOUNDARY

The ammonoid genus Argentiniceras SPATH 1924 (= Andesites GERTH 1925) is described and illustrated from Umia Member (Green Oolitic bed) North of Lakhapar, Western Kachchh, Gujarat. The genus Argentiniceras is a Lower Berriasian form known so far only from South America (Colombia, Peru, Chile, Argentina) and Antarctica (Alexander Island) i.e. the Andean marine faunal province (also known as S. American or SE Pacific) and it is considered a good marker of Lower Berriasian. This is the first report of this genus from anywhere outside the Andean Province. Its discovery in Jurassic/Cretaceous passage beds helps more precise and better delineation of the Jurassic/Cretaceous boundary in Kachchh. Further, together with the earlier reports of some South American Upper Tithonian genera from India, the present discovery also strengthens the evidence of direct marine connection between Andean and Indo-East-African marine faunal provinces near the Jurassic/Cretaceous boundary.