Records of mammals in Mesozoic strata are rare: the earliest are of late Triassic age in Wales, S. Africa and China: two primitive mammal families (Eozo-strodontidae and Kuehneotheridae) are represented in these faunas. There then follows a long time gap until Late Jurassic, when mammals are known from the U.S.A., U.K., Portugal and Tanzania: these faunas include pantotheres, the stock from which almost all the later mammals arose. Between the Late Trias and Late Jurassic, the only known fauna is that of the Middle Jurassic of Stonesfield in Oxfordshire. Thus the discovery of a second site is of great importance: it occurs in the Estuarine Series of Skye in Scotland, and contains a fauna of tritylodonts and docodont mammals. The discovery of this fauna was made in August 1971 by Dr. M. Waldman and Mr. J. B. Dobinson during the course of a search for terrestrial vertebrates in the non-marine strata of Skye.
Since Hugh Miller (1858) described the occurrence of Jurassic vertebrate fossils on the Isle of Eigg, further vertebrates of similar age have been found in the Hebridean region. The richest material so far recovered has been from the Bathonian (Middle Jurassic) of Eigg (Hudson 1966), and the most recent find is that of plesiosaur remains from the Bearreraig Sandstone (Bajocian) near Rigg, Isle of Skye (Hudson & Morton 1969). All the Jurassic vertebrate remains known from this area are those of fish and reptiles and occur in a variety of localities. (Miller 1858, Peach 1910, Arkell