Reviews — Geological Model of Ingleborough. 39 



and consequently, to some extent, of nomenclature." The difficulty 

 to the geologist is that the more the genera and species are split up 

 the less agreement there appears to be about them, and that in course 

 of time palaeontologists are likely to bury themselves in a mass of 

 detail. The present work is indeed drawn up on the lines of the most 

 progressive palaeontology, by an earnest and skilled worker, whose care 

 is beyond praise and whose conclusions are probably as sound as could 

 be. The more interesting stratigraphical results may be given in the 

 author's words: "Regarding the general distribution of the genera it 

 may, therefore, be said that Schelhvienella is found throughout the 

 Carboniferous Limestone and in the Millstone Grit of this country and 

 is known on the Continent from the Lower and Middle Devonian rocks. 

 The so-called 'Orthotetes' umbraculum of the British Devonian deposits 

 probably also belongs to this genus, but is usually so badly preserved 

 as to render diagnosis uncertain. Schuchertella is found in the 

 Carboniferous Limestone and Millstone Grit, while Derlyia occurs in 

 the Carboniferous Limestone, especially in the upper part, and in the 

 Millstone Grit. Orthotetes is only known in this country from the 

 Coal-measures. Meekella has been found in the upper deposits of 

 the Carboniferous Limestone and in the Millstone Grit, and Strepto- 

 rhynchus is known chiefly from the Permian rocks, but occurs also in 

 the higher beds of the Carboniferous Limestone." An excellent plate 

 of figures is given. 



"VI. — Guide to the Geological Model of Ingleborough and District. 

 By Aubrey Strahan, M.A.., Sc.D., F.R.S. Memoirs of the 

 Geological Survey, England and "Wales. 8vo ; pp. iv, 17, with 

 2 plates and 1 text-figure. 1910. Price Ad. 



IN the Geological Magazine for June, 1906 (p. 275), we drew 

 attention to Dr. Strahan's Guide to the Geological Model of the Isle 

 of Purbeclc, an area comparatively simple in plan, but full of interesting 

 and instructive features. In the Ingleborough district the author has 

 to deal, not only with far bolder features, but with unconformities and 

 disturbances of great magnitude. The lower grounds are occupied by 

 a portion of the Ingleton Coal-field, the uplands by Carboniferous 

 Limestone and Toredale rocks, with the grand outlier of Millstone 

 Grit which forms the summit of Ingleborough. The uplands are 

 trenched by certain broad valleys that exhibit Silui'ian, Ordovician, 

 and older rocks (the 'Ingleton Series'), which may be of pre-Cambrian 

 age. The general relations between the physical features and geology 

 are strikingly shown in the two plates. One depicts the model in 

 plain form without names ; the other is an excellent colour-printed 

 geological map of the area, without Glacial drift. The Craven fault, 

 which is reckoned to cause a displacement of more than 5,000 feet 

 near Ingleton, and some other lines of disturbance, are clearly 

 indicated by the physical features. 



The structure of the ground is also illustrated by a longitudinal 

 section across Ingleborough and the Ingleton Coal-field. This would 

 have been more ready of comparison with the map had it been drawn 

 from south-west to north-east, instead of in the opposite direction. 



