Ah account is provided of a new assemblage of small tetrapod. remains from a Mesozoic fissure in a quarry in South Glamorgan. Other fissures in the same quarry have previously yielded remains of small tetrapods belonging to the Hirmeriella association, generally considered to be of Rhaetic or Rhaeto-Lias sic age. On geological grounds the new assemblage -which comprises many thousands of disarticulated. skeletal elements -cannot be younger than basal Sinninrnrian, but the only way in which its age can be determined at all approximately is on the basis of faunal correlation. The fossils are little mineralized, and generally poorly preserved, identified specimens consisting predominantly of teeth. The following forms are represented: (1)Three new species of aphenodontid. Two are congenerio and belong to a new genus. The remaining form also belongs to a new genus. Both genera .re closely related to the Late Nbr'ian genus Clevosaurus; (2) A non- - squamate pleurodont lepidosaur. This form is also a component of the Hirmeriella association; (3) Several species of archosaur; (z) Five distinct forms of the tr.ktylodont Oligokyphus. Three of these are conspecific with the forms which occur at Windsor Hill in Somerset. The remainder -which are probably growth stages -are new; (5) A species of the iaraiyid Thomasia; (6) Five species of' morganucodont. One is Morganucodon watsoni. A second is congeneric with the molar from Hoiwell in Somerset called Eozostrodon problematicus. The three remaining species are new, and. all belong to new and diff?rent genera; (7) One, or several closely related species of a new type of triconoaont; (8) The early therian Kuehneotherium praecursoris. In addition to the identified. material of the above mentioned forms, there are a few mammaliantype teeth of uncertain affinites. It is argued on faimal grounfs that the age of the assemblage is most probably Lower Liassic. It is further argued that the fauna.l components of the assemblage are contemporaneous with those of the Hirmeriella association, and. have hence been drawn from the same terrestrial biota.