410 REVIEWS 



that igneous activity began in late Cretaceous or very early Eocene 

 time and continued till very recently, and that there were several quite 

 distinct periods." 



V. 0. T. 



Permian of " Permo-Carboniferous" of the Eastern Foothills of the 

 Rocky Mountains in Colorado. By R. M. Butters. Bull. 

 Colo. Geol. Surv. No. 5, Part 2, pp. 65-101. Fig. 1. 



This report is concerned with the determination of the age of the 

 Lykins formation, which was assigned by Fenneman to the upper part 

 of the "Red Beds" in the Front Range of eastern Colorado. 



The Lykins formation, which varies considerably in thickness, con- 

 sists of red shales and shaly sandstones, with a few sandy or shaly 

 limestone beds. On the basis of the faunal evidence, the lower part 

 of the Lykins is placed in the Pennsylvanian and an intermediate zone 

 above is tentatively correlated with the Rico formation (Permian(?)) 

 of the San Juan region. "This leaves 100-400 feet of shales to represent 

 the Permian or the remainder of the Permian, the Triassic, and all the 

 Jurassic up to the Morrison." 



V. O. T 



The Geology of Central Ross-shire. By B. N. Peach, L. W. Hinx- 

 man, E. M. Anderson, J. Horne, C. B. Crampton, R. G. 

 Carruthers. Petrological Notes by J. S. Flett. Memoirs 

 of the Geological Survey of Scotland, No. S2, 1913. Pp. 114, 

 pis. 8, figs. 10. 



The western quarter of County Ross is cut off by the great Moine 

 thrust line. The Strathconan fault is the dominant one in the area 

 considered. It is of the type described as a " wrench fault." The direc- 

 tion of the fault line is a little east of north, and the lateral movement was 

 to the northeast on the east side, and to the southwest on the western 

 side. There are many Lewisian inliers thrust upon the younger Moine 

 series. 



The Lewisian gneiss is a basement complex of various rocks of differ- 

 ent ages and includes altered sedimentary rocks that were denuded and 

 affected by contact metamorphism before the deposition of the Moine 

 sediments. 



The Moine series comprises quartzose schists or quartz-biotite 

 granulites and garnetiferous mica-schists or pilitic gneiss, representing 



