RECENT AND FOSSIL RIPPLE-MARK. 
43 
FOSSIL RIPPLE-MARK AND ITS INTERPRETATION. 
FOSSIL RIPPLE-MARK CHARACTERISTICS AND HORIZONS. 
Sandstone formations which are conspicuously ripple-marked 
occur at horizons ranging in age from the Pre-Cambrian to the 
present. These fossil ripple-mark impressions include all of the 
types which have been described in preceding pages. Examples 
of wave formed ripple-mark as it appears in sandstone are 
illustrated both by profiles and photographs in Figure 7 A to G 
and in Plates XXIV, XXV, and XXVI. The appearance of 
Palaeozoic fossil current ripple-mark is shown in Plates XXVII 
and XXVIII and Figure 7 H and I. Resides the two simple 
fundamental types of symmetrical and asymmetrical ripples 
which record precise evidence of the movement of the ancient 
waves and the direction of currents which produced them, the 
sandstones afford good examples of current marks (Plates XXXI 
and XXXIII) and of interference ripple-mark (Plate XXX). 
Even the transverse, secondary, ripple ridges impressed on an 
ancient sand by a shifting wind are found on ripple-marked 
sandstone (Plate XXXII A). 
Geological reports dealing with sandstone formations seldom 
fail to mention ripple-mark as a characteristic of certain beds. 
They generally neglect to state, however, the type of ripple- 
mark represented. Beautifully preserved ripple-mark of both 
symmetrical and asymmetrical type occur in the Huronian. A 
good example of asymmetrical or current ripple-mark from the 
lower Huronian found at lake Chibougamau, Quebec, has been 
figured in a report by Faribault, Gwillim, and Barlow. 1 
Photographs published by Hore 2 show ripple-mark of 
symmetrical type in the Huronian of Ontario. 
In southeastern British Columbia, Daly 3 has described 
a quartzite formation 1,650 feet thick called the Ripple formation, 
which he referred to the Lower Cambrian, but which has since 
been placed in the Pre-Cambrian by Schofield. 4 These quartz- 
1 ‘Report on geology and mineral resources, Chibougamau region, Quebec”, Mines Branch, 
Quebec, 1911, p. 136. 
* Mich. Acad. Sc. Rept., vol. 15, 1913, p. 59. 
1 Geol. Surv., Can., Mem. 38, pt. I, 1912, pp. 155-156, plates XVII and XVIII. 
* Geol. Surv., Can., Mus. Bull. 2, 1914, pp, 79-91. 
