Viola T. Dobosi: Paleolithic Man in the Által-ér Valley (Tata, 1999)

The western boundary of the Gerecse is the so called Tata depression or valley, with the Által-ér as the main water-course of the region. The series of upthrusts sloping steeply along the margins of the Gerecse are spectacular and create a mountain-like impression more than the altitude of the western ridges of the Gerecse, not reaching 500 m altogether, would imply. The Mesozoic limestones of the Vértes and Gerecse Mts. used to serve for long time as raw materials for construction and secured the basis of several factories (cement, lime, „marble" etc.). The phase of the valley extending from Bánhida to Tata-Tóváros is connected to three important Palaeolithic sites, listed in topographical order: Szelim-cave - Vértesszőlős - Tata, in chronological order: Vértesszőlős, Szelim-cave, Tata. These archaeological site undoubtedly prove that at least this very small part of Transdanubia - small even within Hungarian measures - was inhabited for a long time, during several hundred years, by early men and prehistoric people and served as scenery for their life. The geographical space was, however, different from the present one, partly due to the large temporal gap, and these differences can be proved - partly by evident physical reality, partly by the testimony of excavations. What is apparent for all of us is the calcareous tuff escorting the valley of the Által-ér, or in broader sense, the north-eastern margin of the Transdanubian Mid-Mountains in general. The karstic areas of the marginal regions of the mountains always attracted scientists. The medical springs of the region which are still active, the restoration of water balance disturbed during the mining activity, the spectacular forms of calcareous tuff, the analysis of the factors inducing, influencing or ceasing spring activities and the investigation of a large quantity of excellently preserved fossils furnished generations of research workers with challenging tasks. Formation of the calcareous tuff is a phenomenon typical for karstic areas. The resulting rock has several technical names, most typically referred to as freshwater limestone or travertino to distinguish it from different limestone varieties of marine origin like most of the base rock constituting the Transdanubian Mid-Mountain Range. The formation of fresh-water limestone can be outlined, shortly, as follows: The meteoric water infiltrating the cracks of the old limestone is, to some extent, dissolving the limestone along the cracks. The soluted mineral content of the water depends on, mainly, the thickness of the leached limestone. In the case of great faults and sediments of different origin (e.g., the meeting point of loose terrace pebbles and hard limestone) over impenetrable layers these waters with rich soluted mineral content come forth the surface in the form of calcareous springs. 8