Early Devensian sediments and palaeovenvironmental evidence from the excavations at the Royal Oak Portal Paddington, West London, UK

Abstract

This paper discusses the results of the investigation of Pleistocene sediments at the Royal Oak Portal (ROP) site on the new Crossrail scheme near Paddington Station, London. The site was sampled and recorded in May 2011 by archaeologists from Oxford Archaeology commissioned by Crossrail Ltd. The investigation revealed a sedimentary sequence associated with cool climate waterlain deposition towards the edge of the River Westbourne floodplain. During excavation an assemblage of around 100 identifiable large mammal bones was recovered, dating to the Late Pleistocene. The major concentration of bones, from bison and reindeer, was located and excavated from a shallow sequence of sediments. Analysis of the bones indicates that they represent a natural death assemblage, scavenged and subsequently disarticulated, transported by water, exposed and further dispersed and broken by trampling. The site is of regional and national importance because the assemblage derives from a well-constrained geological context, with associated dating evidence suggesting accumulation during the later parts of Marine Isotope Stage (MIS) 5 and continuing within MIS 4. The site is also of significance because it is one of a growing number of recently discovered sites away from the main fluvial archive for the British Middle and Upper Pleistocene. These sites have the potential to add significantly to our understanding of parts of the Pleistocene record that remain difficult to document through the investigation of the more active systems associated with major rivers such as the Thames, Severn or Trent.

Introduction

During the last 15 years there has been an increasing tendency, through archaeological investigations in advance of construction, to investigate Pleistocene sediments for Palaeolithic and palaeoenvironmental remains. This has resulted in the discovery of important archaeological remains at locations such as the gravel quarry at Lynford and within the Ebbsfleet Valley in Kent at Southfleet Road (Boismier et al., 2012, Wenban-Smith et al., 2006). This report discusses the results of one such investigation that uncovered a sequence of Pleistocene sediments belonging to the Devensian (last cold stage). The presence of the sediments was unexpected and were uncovered during excavation of the tunnel boring machine launch chamber at the Royal Oak Portal (ROP) site on the new Crossrail scheme near Paddington Station, London (Fig. 1).

The Crossrail project aims to provide a direct rail link between east and west London and involves boring 21 km of twin bore tunnels eastwards from Paddington Station (Fig. 1A). As part of this project archaeological monitoring was undertaken at Paddington of the excavations associated with the construction of a large chamber to house the tunnel boring machinery. A spread of gravel rich clays and silts was uncovered over a length of 30 m, resting in a slight depression within the surface of the London Clay. The site was sampled and recorded in May 2011 by archaeologists from Oxford Archaeology, commissioned by Crossrail Ltd.