BS 5930 proposes fundamental changes to current practice in the description of soils and rocks. The paper reviews these changes and suggests alternative proposals which provide a workable reconciliation between the aims of the new Code and current practical soil and rock description. The main changes made by the Code and the authors' recommendations are:The distinction between fine soil and coarse soil solely on grading is rejected in favour of description according to engineering behaviour.The distinction between silt and clay solely on the basis of the A-line is supplemented with additional terms for borderline cases.Simplification and extension of terminology for description of secondary constituents of mixed soils.Rejection of proposed weathering classification for rocks as inapplicable, in favour of current practice.Clarification of rock nomenclature to conform with geological conventions.The changes to current practice made by BS 5930 are considered to be a retrograde step and could lead to confusion and errors. The paper also considers the process of sample description and attempts to clarify the definition of terms employed in fracture logging of rock core.The paper calls for a revision and reissue of Section 8 of the new Code.

This paper comments on the status of soil description to BS5930 in ground investigation contracts, gives a briet historical review of the development of modern soil description and deals with problems created by the British Soil Classification System. Proposals are made for working with the current Code and recommendations for the form of a future redraft are given.

G. H. C hild and D. R. N orbury write: From our investigation of the slip when active we would like to make the following comments. Although we did not find shear zones in borehole samples, overnight movement of drill casing in two holes and positive response from a slip indicator in another enabled us to identify the surface of sliding under the embankment side slope which the authors confirmed. We disagree with the authors on the location of the back of the slip, considering the crack in the road to be a secondary feature. In our investigation we considered the primary slip surface to be as shown on Fig. 1 Figures 2 and 3 show the top and toe of the slip on 25 October 1976. The casing of the borehole commenced on the verge and referred to in the paper can be seen in Fig. 2 At this stage major movement had occurred and was all downslope of the road. Figures 3 shows the surface ruckling that had already occurred in the field below. Because of the large crack in the embankment side slope we question the authors’ conclusion regarding the significance of pore water pressures in the fluvioglacial deposits uphill from this crack. Pore water pressures to their line A or above seem most improbable since this would imply flooding of the old A55 road. We agree that the embankment fill was relatively permeable; gradings indicated that it was probably more permeable than the fluvioglacial sand. Therefore, a feature