A deep, fresh railway cut in the moraine southeast of Devil's lake illustrates its complexity of structure, a complexity which is probably no greater than that at many other points where exposures are not seen. The section is represented in Fig. 38. The stratified sand to the right retains even the ripple-marks which were developed when it was deposited. To the left, at the same level, there is a body of _till_ (unstratified drift), over which is a bed of stoneless and apparently structureless clay. In a depression just above the clay with till both to the right and left, is a body of loam which possesses the characteristics of normal loess. It also contains calcareous concretions, though no shells have been found. This occurrence of loess is the more noteworthy, since loess is rarely found in association with drift of the last glacial epoch.[7] [7] An account of loess in connection with the drift of the last glacial epoch is given in the _Journal of Geology_, Vol. IV, pp. 929-987. For a general account of loess, see Sixth Annual Report of U.S. Geological Survey. _The moraine on the main quartzite range._--In tracing the moraine over the greater quartzite range, it is found to possess a unique feature in the form of a narrow but sharply defined ridge of drift, formed at the extreme margin of the ice at the time of its maximum advance. For fully eleven miles, with but one decided break, and two short stretches where its development is not strong, this unique marginal ridge separates the drift-covered country on the one hand, from the driftless area on the other. In its course the ridge lies now on slopes, and now on summits, but in both situations preserves its identity. Where it rests on a plain, or nearly plain surface, its width at base varies from six to fifteen rods, and its average height is from twenty to thirty feet. Its crest is narrow, often no more than a single rod. Where it lies on a slope, it is asymmetrical in cross section (see Fig. 39), the shorter slope having a vertical range of ten to thirty-five feet, and its longer a range of forty to one hundred feet. This asymmetrical form persists throughout all that portion of the ridge which lies on an inclined surface, the slope of which does not correspond with the direction of the moraine. Where it lies on a flat surface, or an inclined surface the slope of which corresponds in direction with the course of the ridge itself, its cross section is more nearly symmetrical (see Fig. 40). In all essential characteristics this marginal ridge corresponds with the _End-Moräne_ of the Germans. [Illustration: Fig. 39.--Diagrammatic cross-section of the marginal ridge as it occurs on the south slope of the Devil's Nose. The slope below, though glaciated, is nearly free from drift.] [Illustration: Fig. 40.--Diagrammatic cross-section of the marginal ridge as it appears when its base is not a sloping surface.]