“…South of the eastern Himalayan syntaxis, the collision-related final marine sediments outcrop as the lower Eocene Rengging Formation and the upper lower Eocene to Middle Eocene Yinkiong Formation in the Siang window region of Assam-Arakan Basin (Tripathi et al, 1978(Tripathi et al, , 1981Tripathi and Mamgain, 1986;Tripathi et al, 1988;Acharyya, 2007;Acharyya and Saha, 2008). Even younger final marine deposits occur in the Bengal basin, where the Sylhet limestone and overlying Kopili Formation are of Middle to upper Eocene age (Samanta, 1965(Samanta, , 1968(Samanta, , 1969Singh and Pratap, 1983;Alam et al, 2003).…”