RECENT ADVANCES IN SCIENCE 31 



52, pt. 2, 175-212). The rocks are divided into two series : a 

 lower, consisting of cherts and black shales with spilitic lavas, 

 associated with intrusives and a group of highly metamorphic 

 rocks of both igneous and sedimentary origin ; and an upper 

 series made up of grits, shales, and limestones, with a basal 

 breccia. The included fossils determine the lower series as 

 of Upper Cambrian age or as belonging to the passage beds 

 between the Cambrian and Ordovician. The upper series is 

 placed with confidence on a higher horizon in the Ordovician. 

 The whole group is greatly affected by lines of crushing and 

 dislocation, which render its relation to the Dalradian Leny 

 Grits to the north very uncertain. 



We are pleased to note that some parts of the British con- 

 tribution to the Handbuch der Regionalen Geologie have reached 

 this country. Dr. J. W. Evans has excellently summarised 

 the stratigraphy of the Devonian (Devonian (Sedimentary) 

 Rocks of Great Britain, Handbuch der Regionalen Geologie, 

 Bd. 3, 1 Abth. The British Isles, 1916, 104-37). I n accord- 

 ance with his early views he believes that most of the Old Red 

 Sandstone is of fluviatile origin. For the genesis of the red 

 marls he cites as parallels the conditions obtaining at present 

 in portions of the Bolivian plateau, and in the interior of South 

 Australia. The Caithness Flags are believed to have been 

 deposited in a region comparable to that of Lake Chad at the 

 present day. 



Sibly, T. F., The Geological Structure of the Forest of Dean, 

 Geol. Mag. 191 8, 5, 23-8. 



According to Prof. H. H. Swinnerton (Proc. Geol. Assoc. 

 1918, 29, 16-28) the Keuper basement beds near Nottingham 

 rest on a subaerially-eroded surface of Bunter rocks, and are 

 defined above by a surface of planation upon which rests the 

 Keuper Waterstones conglomerate. They have a marginal or 

 shore facies along a line running northward from Nottingham, 

 but change to an open-water facies east and south-east of this 

 line. R. L. Sherlock (Geol. Mag. 191 8, 5, 120-5) shows that 

 the two main gypsum bands in the Keuper keep to definite 

 horizons, and serve as valuable datum-lines for the elucidation 

 of Triassic stratigraphy. These horizons occur at approxi- 

 mately constant depths below the Rhaetic, which points strongly 

 to the conformability of the Rhaetic to the Keuper. 



G. W. Lamplugh has summarised present knowledge of the 



